































Hoisting Appliances 


By 

I.C.S. STAFF 


HOISTING 
Parts 3-4 


447 

Published by 

INTERNATIONAL TEXTBOOK COMPANY 


SCRANTON,PA. 


TJ~l-5>-50 

.Zl 


Hoisting, Parts 3 and 4: Copyright, 1906, by International Textbook Company 


Entered at Stationers’ Hall, London 


All rights reserved 


Printed in U. S. A. 




International Textbook Press 
Scranton, Pa. 







CONTENTS 


theirs IiT t u k made . up oi c se Parate parts, or sections, as indicated by 
contentV thV S?i« h ^ Pa ^ e nuI ? bers of each usually begin with 1. In this list of 

the f t e .^i art ? ar r £ Iven ,n . the order in which the y appear in 

the book, and under each title is a full synopsis of the subjects treated. 


HOISTING, PART 3 

Pages 

Hoisting Appliances . 1_43 

Hoist Indicators. 1 _ 5 

Column indicators; Dial indicators; Special indicators. 

Drums and Reels. 6_20 

Cylindrical Drums . 7 _ 8 

Conical Drums . 9-16 

Hoisting with cylindrical drums; Hoisting with conical 
drums; Comparison of cylindrical and conical drums. 

Flat-Rope Reels . 17-20 

Rope Wheels. 21-26 

Koepe system; Whiting system; Modified Whiting sys¬ 
tem. 

Rope Fastenings. 27 

Clutches . 28-31 

Jaw clutch; Band friction clutches; Beekman friction 
clutch. 

Brakes .... 32-43 

Block brake; Post brake; Strap brake; Differential 
brake; Power for brakes; Differential lever; Power 
brakes; Crank brake. 












IV 


CONTENTS 


HOISTING, PART 4 

Pages 

Hoisting Appliances . 1-51 

Sheaves . 1- 5 

Cast-iron sheave; Wood-lined sheaves; Diameter of 
sheave; Rollers and carrying sheaves. 

Cages for Vertical Shafts.. 6-11 

Construction of cage; Safety catches; Multiple-deck 
cages. 

Automatic Dumping Cages. 12-16 

Definition; Slope, or inclined-shaft hoisting; Slope 
carriage. 

Skips, or Gunboats. 17-22 

Definition; Method of loading skips; Method of dumping 
skips; Skip cage. 

Buckets . 23 

Car Locks . 23-24 

Cage Guides . 25 

Landing Fans, or Keeps. 26-28 

Common forms of fans; Hydrostatic fans; Pneumatic 
fans; Cage chairs. 

Head-Frames . 29-45 

Head-frames in general; Types of head-frames; Exam¬ 
ples of various types; Head-frame specification. 

Detaching Hooks. 46-47 

Signaling . 48-51 

Hammer-and-plate signal; Electric bells; Speaking 
tubes; Pneumatic gong signal; Telephones. 














Serial 851C 


HOISTING 

(PART 3) 


Edition 1 


HOISTING APPLIANCES 


TIOIST INDICATORS 

1. The lioist indicator is a mechanism attached to the 
drum shaft of a hoisting engine to show the hoisting 
engineer the position of the cage or skip in the shaft 
throughout the time of hoisting. The use of such indicators 
is sometimes required by law, but there is a great diversity 
of opinion as to the advisability of using them. The objec¬ 
tions to them are that they are liable to get out of order, 
and that in general the use of any automatic device that tends 
to relieve the hoisting engineer of responsibility and constant 
attention to his engine is not to be commended. A hoisting 
engineer, however, depends for his stopping point mainly 
on a mark made on the rope, or on the drum, or on both, 
and uses an indicator mostly as a guide for the position of the 
cage during the hoist. 


TYPES OF INDICATORS 

2. Column Indicators.—A very simple indicator, and 
one that was formerly very commonly used, is made by 
inserting a pin into the center of the end of the drum shaft 
and using this as a miniature drum on which to wind and 
unwind a chain or cord, which corresponds to the hoisting 
rope as the pin corresponds to the drum. This chain or 
cord is led over a pulley placed at the top of a pair of guides, 


COPYRIGHTED BY INTERNATIONAL TEXTBOOK COMPANY. ALL RIOHT9 RESERVED 





2 


HOISTING, PART 3 


representing 1 the shaft, and carries at its end a weight, 
pointer, or gong, representing the cage or car, as shown 
in Fig. 1. 

The different landings in the shaft are marked on the 

guide; and as the pointer 
or gong rises and falls it 
indicates the position of 
the cage in the shaft. If a 
gong is used, pointer also 



may be added and the gong so arranged 
that it will ring at a point some distance 
before the landing is reached and thus 
attract the engineer’s attention. Indica¬ 
tors of this kind, though cheap and easily 
constructed, are not reliable, for the cord 
and chain may stretch or they may overlap 
in winding on the pin, or may bind in the 
pulley and thus indicate a wrong position 
of the cage. 

3. An indicator should have a positive 
motion and be driven by gearing or by 
link belts. Fig. 2 shows a column indicator that consists 
of a screw a working inside of a slotted pipe b, which may 
be of any length necessary. This screw is revolved by 
means of the gears c } which are rotated by the sprocket 



Fig. 2 











































HOISTING, PART 3 


3 


wheel d. A nut e travels up and down the screw a and the 
pointer / attached to the nut indicates the position of the 
cage in the shaft. The pipe standard b is usually painted a 



Fig. 3 

dead black and the different levels may be marked on it with 
chalk or white paint. Chalk marks are not safe, as they may 
be tampered with and the engineer thus misled. 

The pointer a , Fig. 3, is moved by the rotation of the 
screw shaft b y which is revolved by the bevel gears c and d. 
This indicator also registers the number of hoists by means 
of the dials <?, for at each hoist the lower end of the pointer a 
engages a ratchet wheel behind the two dial faces shown and 
thus registers on the dial. 

4. Dial Indicators.—Fig. 4 shows a positive-motion 


a 



indicator that is operated as follows: A worm a on the 
drum shaft b engages with the worm-wheel c on the small 













































4 


HOISTING, PART 3 


shaft cL that is supported by the bearings e. The pointer / is 
rigidly attached to the shaft d and revolves in front of the 
properly marked dial g. 

5. Fig. 5 shows a dial indicator attached to drum 
hoists where the speed of rope is constant for each rev¬ 
olution. The wheel a of this indicator may be a worm-wheel 

working in a worm on the drum shaft, 
as described in connection with the indi¬ 
cator shown in Fig. 4, or it may be a 
sprocket wheel driven by a link belt from 
a sprocket wheel on a drum, or it may 
be a gear-wheel driven directly from 
another gear-wheel on the drum. The 
gear-wheels b revolve a vertical shaft c 
fitted at the upper end with a worm d 
that drives the worm-wheel e placed on 
the end of the pointer spindle. The 
different levels from which hoisting is 
to be done may be painted on the dial, 
or better, they may be placed on mov¬ 
able targets that are clamped to the 
dial and can thus be moved as occasion 
requires. 

Example. —An indicator is desired for a shaft 800 feet deep at 
which the drum of the hoisting engine to be used is 10 feet in diameter; 
what ratio of gearing must be used so that the pointer will make one 
revolution during the hoist? 

Solution. —The circumference of the drum is 31.42 ft. ( 7 xD = 10 
X 3.1416 = 31.416 ft.); hence, the revolutions per hoist are 800 31.42 

= 25.46 revolutions. Then, if the pointer is to make one revolution 
per hoist, the ratio of the gearing will be 25.46 to 1. Ans. 

6. Special Indicators.—One fault of nearly all indi¬ 
cators is that they give a regular movement throughout the 
winding, and the space over which the pointer travels is too 
small to—enable the engineer to land the cage accurately. 
Indicators have been made with a differential motion to the 
pointer, the motion being greater at the time of landing and 
less during the middle of the hoist. They are also made 



Fig. 5 




HOISTING, PART 3 


5 


with two pointers, one operating like the dial indicator above 
described and the other remaining stationary during all the 
hoist but the last few feet, when it moves around its circle. 

7. Where flat ropes are used or where round ropes wind 
on a conical drum, the length of rope wound or unwound is 
different for each turn of the drum. With all the indicators 



thus far described, while the speed with which the indicator 
moves is proportional to the speed at which the drum and 
the drum shaft revolve, it is not proportional to the speed 
of the rope when winding and unwinding on a conical drum 
or on a flat-rope reel. Fig. 6 (a) and ( b) shows two views 
of a compensating dial indicator. By means of the spiral 
form of sheave c , the hand d is made to move equal distances 
around the disk e for equal distances of cage movement in 























6 


HOISTING, PART 3 


the shaft. The rope /passes about the spiral sheave and one 
end is attached at the small end g of the spiral, while the 
other end is fastened to the periphery of the sheave h , which 
takes its motion from the drum shaft or crank-shaft of the 
hoisting engine by means of the bevel gear i. Consequently, 
while the sheave h has a regular motion dependent directly 
on the revolution of the hoisting drum, the pointer d moves 
irregularly, depending on the position of the spiral sheave c; 
that is, whether a small or large diameter of the spiral is 
presented to the rope. The rope j carrying the counter¬ 
weight k is attached to a small circular drum / that is on the 
same shaft as the spiral sheave. The purpose of this cord 
and counterweight is to keep the indicator line / taut and to 
bring the indicator back to position as the cord / unwinds 
from the sheave h. 

8. In order that the pointer may not stand at exactly the 
same point on the dial when the cage is at the top and at the 
bottom, and so that the engineer may be able to distinguish 
between the top and the bottom positions of the cage by the 
pointer, the ratio of the gearing is usually increased by 
allowing one or two extra teeth on the worm-wheel. In the 
example in Art. 5, assume a ratio of 27 : 1; that is, if a 
worm-gear is used, the worm-wheel will have 27 teeth. 

If the pitch of the teeth is f inch, the circumference of the 
pitch circle will be f X 27 = 20.25 inches and the diameter 
6.44 inches. 

The pitch of the worm will, of course, be the same as that 
of the wheel, and its diameter will be whatever is necessary 
to give sufficient strength outside of the shaft, since it bears 
no relation to the ratio of the gearing. 


DRUMS AND REELS 

9. The drum, or reel, of a hoisting engine is the part 
on which the rope winds. It is either keyed fast to the 
engine shaft or is connected to the shaft by means of a clutch, 
the shaft being made extra heavy to carry the strain due to 
the weight of the drum and the pull of the rope. 



HOISTING, PART 3 


7 


CYLINDRICAL DRUMS 

10. The outer part, or shell, of a drum a , Fig. 7, is sup¬ 
ported on rims b , and these rims are connected by arms or 
spiders c with the hubs d. The brake rings e are for the 
band brakes, of which there may be one or two. The part a 
may be lagged with strips of wood bolted to the rims b, the 
heads of the bolts being countersunk. Fig. 8 shows the 
detailed dimensions of a drum 8 feet in diameter having a 
4-foot face designed to carry heavy loads and a large 
amount of rope. The shell is of boiler plate and the spiders 
of cast steel. 


11. The shell may be cast in one piece for small drums 
or built up in sections for large drums, as in Figs. 7 and 8. 



The shell may have a smooth surface, Fig. 8, or it may have 
grooves, Fig. 7, for the rope to lie in as it is wound on the 
drum. On an iron drum without grooves, the rope will 
chafe sidewise; and furthermore if the rope winds on a hard 
flat surface it bears here and there on a single wire and tends 
to flatten, causing internal wear between the wires; while, in 
the case of a rope winding in a groove, it is supported on 
about one-quarter of its circumference, bringing many more 
wires to bear on the drum and dividing the pressure between 
them. A wooden-lagged drum causes less wear on a rope 






































8 


HOISTING, PART 3 


than an ungrooved iron-shell drum, as grooves are gradually 
worn in the lagging, but is not so good as a grooved iron 
drum. It is not good practice to allow a rope to wind on itself, 
and the drum should be long enough to take the full length 
of the rope required for the hoist. At least two turns of the 
rope should be on the drum when the load is at the bottom, 
as the friction between the rope and drum thus greatly 
lessens the strain coming on the rope at the point where it is 



fastened to the drum. Allowance for two or three additional 
turns of the rope should also be made so that the cage may 
be hoisted above the landing. 

The shell usually has a flange at each end, as shown in 
Figs. 7 and 8, but it may have a flange at one end only, or 
may be without flanges entirely. If, however, the flanges 
are not used, the drum must be extra long to prevent the rope 
running off the end. If the drum is very long, a third spider 
is added midway between the other two to stiffen it against 
collapse. 

Example.—F ind the length of a drum 6 feet 3 inches in diameter 
necessary to hold 1,000 feet of li-inch wire rope. 
















































HOISTING, PART 3 


9 


Solution. —The diameter from center to center of the rope when 
wound on the drum is 6 ft. 3 in. plus in., or 6 ft. in., which is 
equal to 19.96 ft. (approximately 20 ft.) of circumference. Then, to 
1 000 

wind 1,000 ft. will require ~ Q - = 50 turns on the drum. Allowing two 

turns of the rope to protect the fastening and three turns in case of 
overwinding, gives fifty-five turns to be allowed for on the drum. If 
the drum is of iron with grooves turned in it, i in. must be left between 
adjacent parts of the rope, or l£ in- from the center of one turn to the 
center of the next. Then, 55 X 1| = 82£ in. plus f in. at each end 
= 84 in., or 7 ft. for the length of the drum between the flanges. Ans. 

If the drum has wooden lagging, clearance need not be allowed 
between two adjacent coils of rope, as in this case the rope winds 
against itself and so takes up only l\ in. It will then be 55 X H in. 
= 68f in., or 5 ft. 8f in. long (say 5 ft. 9 in.). Ans. 


CONICAL DRUMS 

12. In hoisting in balance from deep shafts with cylin¬ 
drical drums, if no tail-rope is used, or in hoisting from a 
single shaft with an unbalanced cage, the hoisting engine is 
not loaded equally at different points of the hoist owing to the 
gradually changing weight of the unbalanced rope. The 
following illustrations will further explain this. 

13. Hoisting With a Cylindrical Drum. —Suppose 
that, from a single-compartment vertical shaft 1,000 feet deep, 
it is required to hoist each trip a load, including friction, of 
11,000 pounds made up as follows: 

Pounds 


Weight of material. 4,000 

Weight of car. 3,000 

Weight of cage. 3,000 

Friction, 10 per cent. 1,000 

Total .11,000 


If a lf-inch cast-steel rope weighing 3 pounds per foot is 
used, winding about a drum 7 feet in diameter, the weight of 
rope is then 3 X 1,000 = 3,000 pounds and the load on the 
rope, when the cage is at the bottom, is 11,000 + 3,000 
= 14,000 pounds, while at the top the load on the rope is 
only 11,000 pounds. The moment of the load at the bottom 








10 


HOISTING, PART 3 


is then the load 14,000 multiplied by the radius 3i, or 14,000 
X 3i = 49,000 foot-pounds; and at the top, 11,000 X 3a 
= 38,500 foot-pounds. This shows that the load against the 
engine is much greater at the beginning than at the end of 
the hoist. 

14. Take now a double-compartment vertical shaft of 
the same depth as in Art. 13 and assume the same amount 
of material hoisted at a trip, in the same mine car and on the 
same cage; but that an empty car and cage are lowered in 
one compartment while the loaded car and cage are hoisted 
in the other. The two cars and the two cages will balance 
each other, and the loads will be as follows: At the begin¬ 
ning of the hoist, when the loaded car and cage are at the 
bottom, the gross load is 14,000 pounds, made up as 


follows: 

Pounds 

Weight of material. 4,000 

Weight of mine car. 3,000 

Weight of cage. 3,000 

Friction, 10 per cent, of above . . 1,000 

Weight of rope. 3,000 

Total .143X30 


Multiplying this by the radius of the drum, the gross turn¬ 
ing moment is 14,000 pounds X 3i feet = 49,000 foot-pounds, 
as before, but there is a counterbalancing load of 6,000 pounds, 


made up as follows: 

Pounds 

Weight of mine car.3,000 

Weight of cage.3,000 

Total.63300 

Less friction, 10 per cent. 600 

M00 


This means a counterbalancing load moment of 5,400 pounds 
X 3J- feet = 18,900 foot-pounds. The net load moment to 
be overcome by the engine at the beginning of the hoist is, 
therefore, 49,000 — 18,900 = 30,100 foot-pounds. 













HOISTING, PART 3 


11 

At the end of the hoist there is a gross load on the loaded 


side of 11,000 pounds, made up as follows: 

Pounds 

Weight of material .... 

4,000 

Weight of mine car . . 

3,000 

Weight of cage. 

3,000 

Friction, 10 per cent. 

1,000 

Total . 

11,000 

This is equal to a gross load moment of 11,000 pounds 

X 31 feet = 38,500 foot-pounds, but there 

is a counterbal- 

ancing load of 8,100 pounds, made up as follows: 


Pounds 

Weight of mine car. 

. 3,000 

Weight of cage . 

. 3,000 

Weight of rope . 

. 3,000 

Total. 

. 9,000 

Less friction, 10 per cent, of 6,000 

. 600 


8,400 

This is equal to a counterbalancing load moment of 
8,400 pounds X 3i feet = 29,400 foot-pounds, and leaves a 

net load moment against the engine of 

38,500 - 29,400 

= 9,100 foot-pounds. In other words, the load moment 


that the engine has to overcome varies from 30,100 foot¬ 
pounds at the beginning of the hoist to 9,100 foot-pounds 
at the end of the hoist. 

15. Hoisting With Conical Drums.—Conical drums 
are designed to make the work of the engine as nearly uni¬ 
form as possible throughout the hoist. To accomplish this, 
when the cage is at the bottom of the shaft, and the load 
is therefore heaviest, the rope winds on that part of the 
drum having the smallest diameter. As hoisting continues, 
the rope winds on a gradually increasing diameter of drum,- 
and when the cage is at the top of the hoist, and the load 
therefore least, the rope is winding on that part of the drum 
having the greatest diameter; in this way, the moment of 
the load at every point of the hoist is approximately the 
same. The great difference in the loads at different parts 












12 


HOISTING, PART 3 


of the hoist is due mainly to the variation in the weight of 
the rope hanging from the drum; hence, the less the weight 
of the rope in proportion to the total load on the engine, the 
more nearly uniform is the load on the engine. 


16. Fig. 9 (a) shows the condition at the beginning of 



(a) 


Fig. 9 


0 >) 


the hoist when conical drums are used. Cage a is at the 
bottom and carries a loaded car; cage b is at the top and 
carries an empty car. The net moment that the engine must 
overcome is the sum of the weight of the material to be 
hoisted, weight of the cage and car at a , and the weight of 
the rope attached to a , multiplied by the small radius r of the 
drum, minus the weight of the car and cage at b, multiplied 
by the large radius R of the drum. 

Fig. 9 {b) shows the condition of things at the end of the 
hoist, when the cage a is at the top and cage b at the bottom. 
The loaded car and cage a , whose rope in Fig. 9 (a) was 


















































HOISTING, PART 3 


13 


winding on the smallest diameter of the drum, is now at the 
top and the rope is winding on the largest diameter of the 
-drum. The cage b with the empty car is now at the bottom 
and the rope is unwinding from the smallest diameter of 
the drum. The net moment that the engine must over¬ 
come in this position is equal to the sum of the weight of the 
material hoisted, the weight of the cage a and the car, multi¬ 
plied by the larger radius R of the drum, minus the sum of 
the weights of the cage b , the car, and the rope, multiplied 
by the small radius r of the drum. 

17. If the moment of the load against the engine at 
the beginning of the hoist is to equal that at the end of the 
hoist, it is possible to determine what relative diameters of 
drum will produce such an effect, as follows: 

Let W m = weight of material hoisted; 

W c — weight of cage and car; 

W r ■— weight of rope; 

R = large radius of drum; 
r = small radius of drum. 

The load moment may be calculated by including friction 
as tV of the total weight hoisted, except the weight of the 
rope, as shown in Art. 14; or the friction may be disregarded 
without serious error. Then, under the conditions shown in 
Fig. 9 (a), and disregarding friction, 

Load moment = (W m - h W c -b W r )r — W c R (1) 
and under the conditions shown in Fig. 9(£), 

Load moment = ( W m + W C )R - ( W c + W r )r (2) 

Placing formula 1 = formula 2, 

( Wm -f Wc) R - ( Wc + W r ) r = ( Wm 4- W e + W r ) r - W C R, 


and 


R = r 


( W m + 2 W e + % W r ) 


(3) 


(W m +2W e ) 

% 

Since the diameter of a drum is generally given instead of 
the radius, it follows that if D = larger diameter, d = smaller 
diameter, and then, since D = 2R and d = 2r, formula 3 
may be written 


D = d 


(Wm + 2W,+ 2W r ) 

(Wm+2W C ) 


(4) 


447—2 




14 


HOISTING, PART 3 


Formula 4 gives only approximate results, which are, 
however, sufficiently accurate for the mine superintendent’s 
use, and for this reason friction has been omitted, as it would 
make the formula much more complex. It may be expressed 
as a rule as follows: 

Rule. — To find the large diameter of a conical drum , mul¬ 
tiply the small diameter by the sum of the weight of the material 
to be hoisted , twice the weight of the cage and car , and twice the 
weight of the rope; divide this product by the sum of the weight 
of the material, and twice the weight of the cage and car. 



Applying this rule to the problem given in Art. 14 and 
omitting friction, 

n _ 7(4,000 + 12,000 + 6,000) n 0 , 

° ~ (47000 + 12,000)- = 9 6 feet 

The drum would then be 7 feet in diameter at the small 
end and 9 feet 74 inches at the larger end. 





























HOISTING, PART 3 


15 


18. Fig. 10 shows a special form of combined conical 
and cylindrical drum designed for hoisting a total balanced 
load of 25 tons through a vertical height of 550 feet. 

Fig. 11 shows a combined conical and cylindrical drum; 
an unusual feature is the rope reel shown at each end of the 
drum, which permits of properly storing a few hundred feet 



of extra rope, allowing the rope to be lengthened, when 
needed, without splicing. 

19. Comparison of Cylindrical and Conical Drums. 
The disadvantages of the cylindrical drum lie entirely in the 
fact that the load on the engines is variable, but it is possi¬ 
ble to overcome this disadvantage by adding a tail-rope to 
the cages to balance the weight of the rope. This system 
gives its best results where hoisting is done from one level 
only, but in deep hoisting it is impracticable because of the 
extra weight added and because of possible excessive sway¬ 
ing of the rope. 

The conical drum has two strong points in its favor: first, 
the load on the engine may be nearly equalized during the 















































16 


HOISTING, PART 3 


entire hoisting period; and, second, the starting of the 
engines with the load requires less power. 

The disadvantages of the conical drum are as follows: To 
maintain a certain average speed of hoisting, the speed 
toward the end of the hoist is of necessity higher than the 
average and comes at a time when a slowing up should be 
taking place, so that more care must be exercised when 
making the landing. To prevent the rope from being drawn 
out of the grooves, the latter must be made deep and with a 
large pitch, thereby increasing the width of the face or 
length of the drum. In making a landing, when the rope 
is on the conical face, the rope must be kept taut, as any 
slackness will permit the rope to leave the groove, with the 
result that all the rope will pile up in the bottom grooves of 
the drum allowing the cage to drop into the mine, unless it 
is resting on the chairs. If there are several levels to be 
hoisted from, the equalizing of the load on the engines can 
only be realized for one level; for all other levels this advan¬ 
tage will be lost. For large depths, conical drums become 
very long and require correspondingly long leads from head- 
frame to drum. To hold the same amount of rope, conical 
drums are heavier than cylindrical ones, and as a result, the 
power required in starting the load is somewhat increased 
owing to the greater inertia of the rotating parts. 

Some of these disadvantages have been overcome by 
making a combination of cone and cylindrical drums. The 
drums are so designed that the landing takes place only 
when the rope is on the cylindrical portion of the drum. For 
deep hoisting, the greater diameter of the drum and its length 
must be inconveniently large if the load is equalized. The 
length and diameter can be reduced by making one-half of the 
drum cylindrical and by having the rope from each end wind 
on the same cylindrical portion of the drum. In all cases, how¬ 
ever, these modifications are made at the expense of the equal¬ 
ization of the load on the engines, and it is not possible to 
obtain the latter without including some serious disadvantage. 

There are certain objections to both cylindrical and conical 
drums: their great size and weight, for large hoists, make 


HOISTING, PART 3 


17 


them very expensive; their width necessitates placing the 
engines far apart, which adds to the cost of the engines, 
foundations, and buildings; the great weight of the drums is 
also objectionable, because it forms a large part of the mass 
to be put in motion and brought to rest at each hoist. 


FLAT-ROPE REELS 


20. To overcome the objections to conical and cylindrical 
drums, several other systems of hoisting have been tried, 
among them being one that uses a reel, Fig. 12, and a flat 




rope. The hub a is increased in diameter, above what is 
necessary for strength, to such a size as is suitable to wind 
the rope on. It is then cored out from the inside, so as not 
to contain too great a mass of metal. 

The arms b of the reel extend radially from the hub to 
confine the rope laterally when it is all wound on the drum. 
These arms are connected at their outer ends by a con¬ 
tinuous flange c , which flange is flared out, as shown at d , so 
as to take in the rope easily, if it is deflected at all sidewise. 

In the larger-sized reels, the arms are bolted to the hub, 
and often the outer rim connecting the arms is omitted. 
Hardwood lining was formerly used on the arms under the 









































18 


HOISTING, PART 3 


impression that the wear on the rope would be less than with 
bare iron arms, but sand and grit become embedded in the 
wood and grind the rope. Polished iron arms with rounded 
corners and lubricated with oil or tar are best. The end of 
the rope is fastened in a pocket e provided for it in the hub. 

The rope winds on itself, so that the diameter of the reel 
increases as the hoist is made and as the load due to the 
weight of the rope decreases. This serves to equalize the 
load due to the rope in the same manner as the conical drum. 
Two reels are generally put on the same shaft, and while one 
is hoisting from one compartment of the shaft the other is 
lowering into another compartment. The periphery of the 
hub where the rope winds should not be round but of grad¬ 
ually increasing radius, for if a flat rope be wrapped about a 
round hub the rope will have to abruptly mount itself at the 
end of the first revolution and so on for every revolution. 
The radius of the hub should increase at such a rate as to 
raise the rope an amount equal to its thickness in the first 
wrap, so that it will wind on itself without jar at the point of 
attachment, as well as on succeeding wraps. 

21. In America, it is customary to wind on reels of small 
diameter, that is, starting at 3 or 5 feet and increasing to 
8 or 12 feet; but several large plants have been built with 
reels starting at 8 feet and increasing to 19 feet. In England, 
reels have been made starting at 16 feet and increasing to 
20 or 22 feet. Such large reels are easier on the rope but 
require large engines, as hoisting in balance is used to only 
a slight extent. The large reel is easy on the rope, both 
from the fact that it bends the rope but little and also gives 
less pressure on the bottom wraps, as each wrap adds to the 
pressure. These reels are driven by means of plain jaw or 
friction clutches. 

The wear of a flat rope is excessive and the rope itself 
costs more than a round rope of the same strength, does not 
last as long, and requires more care and attention. 

22. Calculating Size of Flat Rope and Reel.—The 
calculation of the size of a flat rope for given work is not so 


HOISTING, PART 3 


19 


simple as that of a round rope, as there is a variable factor in 
the width and thickness of the rope that must be taken into 
account. To illustrate the method of calculation, suppose 
that it is required to hoist 5,000 pounds of material in a 
3,000-pound skip from a vertical two-compartment shaft 
2,000 feet deep under conditions requiring a factor of safety 
of about 9 for the rope. 

The determination of the size of the rope and the small 
and large diameters of the reels must proceed together. 
The latter calculations are performed in much the same 
manner as for conical drums. 

Referring to Table relating to flat wire ropes in Hoisting , 
Part 2, it is found that a flat steel rope 6 inches by i inch in 
size and with a breaking strength of 150,000 pounds weighs 
5.1 pounds per foot; hence, 2,000 feet of it weighs 2,000 X 5.1 
= 10,200 pounds. The total load on the rope will then be 
19,000 pounds, made up as follows: 

Pounds 


Weight of material. 5,000 

Weight of skip. 3,000 

Friction, 10 per cent. 800 

Weight of rope.1 0,200 

Total .19,000 


This rope gives a factor of safety of = 7.8, which 

is not quite enough when figured from the dead load without 
that due to acceleration. 

An 8" X i" rope with a breaking strength of 200,000 pounds 
weighs 6.9 pounds per foot; hence, 2,000 feet of it weighs 
2,000 X 6.9 = 13,800 pounds. The load on the rope will then 
be 22,600 pounds, made up as follows: 

Pounds 


Weight of material. 5,000 

Weight of skip. 3,000 

Friction, 10 per cent. 800 

Weight of rope.13 ,800 

Total . 22,600 














20 


HOISTING, PART 3 


This rope gives a factor of safety of = 8.8. Sub- 

A A , t)UU 

stituting the foregoing weights of material, skip, and rope in 
formula 4 , in Art. 17 , gives 

D = d (5,000 + 6,000 + 27,600) 

(5,000 -f 6,000) 

Hence, the equation of moments is D — 3.5 d. In other 
words, the large diameter, or that of the last coil of rope, 
should be 3.5 times the small diameter, or that of the reel 
hub. 

23. Fig. 13 represents a coil of flat rope whose greater 
diameter D and smaller diameter d are to be determined. 

The area of the hub about 
which the rope is to coil is 
i 7 r Z 2 , while the area in¬ 
cluded by the outer coil of 
rope is i tt D 2 \ hence, the 
arpa of annular space oc¬ 
cupied by the rope is \tt D 2 
- i tt d : = }tt (D 2 - d 2 ). 

Such values for D and d 
must be chosen that the 
equation of moments in 
Art. 22 is satisfied, while 
the area i tt (ZT — d 2 ) must 
correspond to the space occupied by the given rope when 
rolled. 

2 000 X 12 

Illustration.— 2,000 feet of rope | inch thick requires — L —-- 

= 12,000 square inches in which to be coiled. To satisfy the equation 
of moments, D must equal 3.5 d\ hence, to satisfy both these conditions 
-i-7r[(3.5fl0 2 -rf 2 ] = 12,000; 
d «= 37 inches, or 3 feet 1 inch; 

D = 37 X 3.5 = 129.5 inches, or 10 feet inches. 

The dimensions of the reel will then be: diameter of hub 3 feet 
1 inch; width between flanges, 8£ inches, allowing \ inch on each side 
of the rope for clearance; diameter of the flanges where they flare, 
10 feet 9£ inches 


















HOISTING, PART 3 


21 


HOPE WHEELS 

24 . Koepe System.—In its lightest form, a drum 
requires a large amount of power to set it in motion, which 
power is absorbed by the brake and lost when it is brought 



sheave due to its traveling from one end of the drum to the 
other, is not only a disadvantage and possible cause of 
accident, but it is a source of wear. To overcome these 
objections and also the great cost of large cylindrical or 
conical drums, the Koepe system of hoisting, shown in 
Fig. 14, was devised by Mr. Frederick Koepe. A single 
































22 


HOISTING, PART 3 


grooved driving sheave a is used in place of a drum. The 
winding rope b passes from one cage A up over a head-sheave, 
thence around the sheave a and back over another head- 
sheave, and down to a second cage B\ it encircles a little over 
half the periphery of the driving sheave and is driven by the 
friction between the sheave and rope. A balance rope c 
beneath the cages and passing around the sheave d gives an 
endless-rope arrangement with the cages fixed at the proper 
points. The driving sheave is stronger than an ordinary 
carrying sheave, as it has to do the driving and is usually 
lined with hardwood, which is grooved to receive the wind¬ 
ing rope, the depth of the groove being generally equal to 
twice the diameter of the rope. Instead of being placed 
parallel, the head-sheaves are placed at an angle with each 
other, each pointing to the groove in the driving sheave, 
thus reducing the side friction of the rope on the sheaves. 

The system has been in successful operation since 1877, 
and experiments made on it have determined that, with a 
rope passing only one-half turn around the drum sheave, the 
coefficient of adhesion with clean ropes is about .3. If the 
ropes are oiled, the adhesion becomes less, and sometimes 
slippage occurs, producing not only wear of the driving- 
sheave lining but giving an incorrect reading of the hoist 
indicator and thus possibly producing overwinding, unless 
the position of the cage is indicated by marks on the rope, 
or unless the engineer can see the cage. 

At the end of the hoist, if the upper cage is allowed to 
rest on the keep, its weight and the weight of the tail-rope 
are taken from the hoisting rope, and there is then not 
enough pull on the hoisting rope to produce sufficient friction 
with the drum sheave to start the next hoist. To prevent 
this trouble, the keeps are dispensed with, or the rope is 
made continuous and independent of the cage. To do this, 
crossheads are placed above and below each cage and con¬ 
nected by ropes or chains outside of the cages. The bridle 
chains are then hung from the top crosshead, and when the 
cage rests on the keeps, the weight of the winding and tail- 
ropes remains on the driving sheaves. 


HOISTING, PART 3 


23 


25 . Advantages and Disadvantages of the Koepe 
System. —With this system, only one driving sheave is 
necessary for the operation of two compartments, and it is 
light, inexpensive to build, and very narrow, admitting of a 
short sheave shaft and small foundations. This system per¬ 
mits a perfect balance of rope and cage, so that the work to 
be done by the engine is uniform, except for the accelera¬ 
tion, and consists only in lifting the material and overcoming 
the friction. There is no fleeting of the rope between the 
driving sheaves and the head-sheaves. 

The system has the following disadvantages, which pre¬ 
vent its being used to any considerable extent: Liability to 
slippage of the rope on the drum; if the rope breaks, both 
cages may fall to the bottom; hoisting from different levels 
cannot be well done, for, since the cages are at fixed dis¬ 
tances from each other, the length of the rope is such that 
when one cage A is at the top, the other cage B is at the 
bottom. If hoisting is to be done from the bottom, this is 
satisfactory, but if hoisting is to be done from some upper 
level, cage B y which is at the bottom, must be hoisted to that 
level to be loaded before it can go to the top. Then, when 
cage B goes to the top with its load, cage A must go to the 
bottom, wait there while cage B is being unloaded, and then 
be hoisted to the upper level to receive its load. For each 
trip, therefore, the time required for a cage to go from the 
bottom to the upper level and be loaded is lost; and two 
movements of the engines are necessary for a hoist instead 
of one. 


26 . The Whiting System. —This is a system of hoist¬ 
ing with round ropes, in which two rope wheels placed tan¬ 
dem are used in place of cylindrical or conical drums. As 
shown in Fig. 15, for a two-compartment shaft the rope 
passes from one cage a up over a head-sheave c , down under a 
guide sheave d, and is then wound three times about the rope 
wheels e and /, to secure a good hold, then around a fleet 
sheave g , and back under another guide sheave h , up over 
another head-sheave i, and down to the other cage b. When 



24 HOISTING, PART 3 

the system is to be used for a single-compartment shaft, one 


I 
I 

i 
• 

end of the rope carries the cage and the other end carries ; 
balance weight, which is run up and down in a corner of th< 


Fig. 15 























































HOISTING, PART 3 


25 


shaft. A balance rope below the cages, as shown, is gen¬ 
erally used, though it is not essential to the working of the 
system, as it is in the Koepe system. When sinking a shaft, a 
balance rope cannot be used as it interferes with the work at 
the bottom of the shaft. 

The drums or wheels e , / are light, inexpensive, and narrow, 
thus permitting short sheave shafts and small foundations. 
They are lined with hardwood blocks, each lining having three 
rope grooves turned in it. The main wheel e is driven by a 
hoisting engine, which may be either first or second motion. 
The following wheel / is coupled to the main wheel by a 
pair of parallel rods, one on each side, like the drivers of a 
locomotive. As the rope wraps about the wheels e, / three 
times, there are six semi-circumferences of driving contact 
with the rope, as compared with the one semi-circumference 
in the Koepe system, and there is no slipping of the rope on 
the wheels. The following wheel / is best tilted or inclined 
from the vertical an amount equal, in the diameter of the 
wheels, to the pitch of the rope on the wheel, so that the rope 
may not run out of its groove and may run straight from one 
wheel to the other without any chafing between the ropes 
and the sides of the grooves. 

The capacity of the wheels e> / is unlimited, while grooved 
cylindrical drums, conical drums, and reels will hold only 
the fixed length of rope for which they are designed. 

As shown by the dotted lines, the fleet sheave g is 
arranged to travel backwards and forwards, in order to 
change the working length of the rope from time to time to 
provide for an increased depth of shaft, and for the changes 
in the length of rope due to stretching and when the ends 
are cut off to resocket the rope. The fleet sheave g is moved 
a distance equal to half the change in the length of rope. 

27 . Hoisting from intermediate levels can be readily 
done with the Whiting system; for instance, if the cage a is 
at the top and cage b at the bottom, and hoisting is to be 
done from some upper level, it is only necessary to run the 
fleet sheave g out, and thus shorten the working length of 


26 


HOISTING, PART 3 


the rope until cage b comes up to the upper level. It can 
then be loaded and go to the top. While cage b goes to the 
top, cage a descends to the same level, where it can be 
loaded while cage b is being unloaded, and can then go 
directly to the top without any of the lost time, as is the case 
in the Koepe system. 

The system permits a perfect balance of rope and cage, so 
that the work to be done by the engines is uniform, except 
for the acceleration, and consists only in lifting the material 
and overcoming the friction. 

There is no fleeting of the rope, so the rope wheels can 
be placed as close to the shaft as may be desired. 

28. This system was tried as early as 1862 in Eastern 
Pennsylvania, but it was not used extensively because hoist¬ 
ing from great depths was not necessary, since, for depths of 
less than 1,000 feet, cylindrical and conical drums are quite 
satisfactory. In the Lake Superior copper region, there are 
now three Whiting hoists, two of which are probably the 
largest hoisting plants in the world. Each plant consists of 
a pair of triple-expansion, vertical, inverted-beam engines, 
driving direct a pair of 19-foot drums. The high-pressure 
cylinders are 20 inches in diameter, the intermediate cylinders 
32 inches, and the low-pressure cylinders 50 inches, and all 
six of them have a 72-inch stroke. The rope used is a 
2i-inch plow-steel rope and hoists 10 tons of material at a 
trip, in one case from a depth of 4,980 feet, the deepest shaft 
in the world. Several plants on the Whiting system have 
been built in England, and two or more are working in 
South Africa. 

29. Modified Whiting System.—A modification of the 
Whiting system is' sometimes used in which a large drum 
keyed to the crank-shaft replaces the small tandem drums, and 
even the slight probability of the rope slipping in the Whiting 
system is thus obviated. One rope is fastened to one end of 
the drum, and the other rope to the other end in such a way 
that while one is winding on the other will be winding off the 
drum. One rope passes directly to the head-sheave while 


HOISTING, PART 3 


27 


the other passes first around a fleet sheave, similar to that 
Used for the Whiting system, but preferably placed horizon¬ 
tal, and thence to the head-sheave. This system possesses 
the same advantages as the Whiting system except that the 
depth of hoist is limited by the size of the drum, and that 
there is a fleet of the rope. Up to the limiting depth, as 
determined by the size of the drum, this system can be used 
with equal economy for any depth. This hoist, as well as 
the Whiting, is therefore especially suitable for a place where 
one mining company operates several mines, for it enables 
the company to select one size for all their permanent work, 
with all the advantages that come from duplicate machinery. 



ROPE FASTENINGS 

30 . A common method of fastening a rope to a drum, 
Fig. 16 ( a ), is to pass the rope through a hole in the drum 
rim and then around the shaft, 
clamping the end to the rope 
between the shaft and shell, as 
shown. Care should be taken 
to make the radius of curvature 
of the hole at a as large as pos¬ 
sible so that the rope will not be 
bent any sharper than is neces¬ 
sary. When an iron drum is 
used, the thickness of the rim 
does not afford enough depth in 
which to bend the rope and it is 
necessary to build in a pocket 
for the purpose, as shown at 
Fig. 16 ( b ). It is well to make 
both sides of this pocket with a 
long radius to avoid damaging the rope in case all the rope 
is accidentally unwound and the drum backed so as to bring 
the rope against the other side of the pocket. 



Fig. 16 




28 


HOISTING, PART 3 


CLUTCHES 

31. It is often desired to have the drum of a hoisting 
engine run loosely on the engine shaft, so that it may run 
independently of the engine. With such loose-running 
drums, the engine generally runs only in the direction 
required to hoist the load, while the cage is lowered entirely 
by means of the brake. In this way, one engine provided 
with several drums may be used for hoisting from several 
shafts or from several levels in the same shaft at the same 
time. Such a loose-running drum is connected to the engine 
shaft when a load is to be hoisted by means of a clutch, of 
which there are two forms commonly used for hoisting 
machinery: jaw or piston clutches and friction clutches. 

32. Jaw Clutch.—Fig. 17 shows a jaw clutch, one- 
half a of which is shown ready to be bolted to a drum or 

flat-rope reel, which is 
loose on the shaft b. The 
other half c of the clutch is 
moved back so that the 
jaws d are not in contact 
with the jaws e on the part 
a. The half c slides freely 
on a feather key /, which is 
driven tightly into a deep 
key seat in the shaft b\ a 
collar g, fitting loosely in 
a groove in the hub of c } is 
provided with trunnions h 
on each side; levers i con¬ 
nect these trunnions with the lever j attached to a suitable 
handle, by means of which the clutch is made to slide end¬ 
wise on the shaft so that the jaws d engage or disengage 
the jaws e and thus connect or disconnect the drum or reel 
from the clutch. There are generally four or six jaws d 
that engage the same number of jaws e on the drum, and it 
is necessary to have little or no play between d and e when 



Fig. 17 







HOISTING, PART 3 


29 


the clutch is connected or there will be too much shock. 
The clutch is about 2 feet in diameter, and the jaws are 3 
or 4 inches deep for the average 20" X 48" first-motion 
hoisting engine. Instead of the clutch being fastened to 
the shaft by feather keys, the shaft may be hexagonal where 
the clutch slides on it and the clutch is machined to match. 
Jaw clutches are made of either cast iron or cast steel, and 
should be in halves, for convenience of repair, and securely 
bolted together. 

33. Band Friction Clutches.—Fig. 18 shows a band 



Fig. 18 

friction clutch that is attached to and revolves with the 
shaft a. The winding drum runs loosely on the same shaft 
and has a driving-band ring or seat b on one end; when the 
ring c of the clutch is tightened by means of the mechanism 
shown, the clutch and driving band become practically 


447—1 

















30 


HOISTING, PART 3 


one piece and the drum revolves with the clutch. The 
clutch is constructed as follows: The driving disk d keyed to 
the driving shaft a is connected to one end of the ring f by a 
fixed arm e , which is bolted firmly to the disk d and revolves 
with it; a movable arm / that connects with the other end of 
the band c turns on the pin g. When the band c is loose, it 
can revolve about the seat b without touching it, but the 
band can be tightened and made to clamp b either when 
revolving or standing still, as follows: The sliding sleeve h 
may be caused to slide about 6 inches along the hub of the 
disk d by levers (not shown) that take hold of trunnions i 
on a ring on the sliding sleeve; this sleeve is connected to 
the movable arm / by a link /, and when the sleeve is on the 
end of the hub the link stands at an angle of about 60° with 
the shaft; by sliding the sleeve toward the disk d, the link is 
made to move the arm / about li inches at its outer end and 
to thus tighten the driving band c y so that it grips the 
ring b. The adjusting nuts k take up the wear of the 
wooden blocks with which the ring c is lined. Band lifters l 
hold the band clear of the ring when it is loose. The clutch 
shown is built to run in the direction indicated by the arrow, 
but such clutches may be built to run in either direction; 
they should always be run in the direction for which they are 
designed, so that the load may always come on the fixed 
arm. If the band be tightened slowly, there will be no 
.sudden start or jerk on the rope, as the slip of the band will 
prevent the entire force of the grip taking effect at once; 
and after the drum reaches full speed, there is little or no 
slipping of the driving band. It is best to keep the band 
only just tight enough to do the work, for should the car get 
off the track, or be overwound, or should a cage stick in the 
shaft for any reason, the band will slip and thus become a 
safety appliance, and not strain or break the rope, shaft tim¬ 
bering, or machinery, as would be the case if a positive 
clutch, Fig. 17, were used. 

34. The Beekman Friction Clutch. —A simplp fric¬ 
tion clutch is shown in Fig. 19, in which a is a section of the 


HOISTING, PART 3 


31 


drum shell. The wooden blocks b bolted to the side of the 
gear-wheel c are made of suitable shape to conform to the 
V-shaped groove d in the side of the drum. The steel 
spring e between the two steel washers /, / disengages the 
clutch, as soon as the pressure is relieved, by reversing the 
motion of the lever g and screw h from the opposite end of 
the drum. When the levers is turned, the screw h is forced 



against the end of the pin i, which, in turn, presses the cross- 
key/ against the collar k, forcing the drum against the blocks b 
and frictionally engaging the gear-wheel c. This drum shaft 
is prevented from moving endwise by means of the collar l 
and the grooves m in the babbitted pillow-block. The wide 
bearings of the drum on its shaft are lubricated by means of 
the pipes n. 

A clutch is often used to change the length of the hoisting 
rope when hoisting from two or more lifts or levels. In 
this case the shaft carries two drums, one of which is fixed 
to the shaft, while the other is provided with a friction clutch. 
When it is desired to change the length of the rope, the cage 
attached to the loose drum is brought to, say, the upper land¬ 
ing. The cages both resting on the wings, the clutch is 
loosened and the other cage attached to the fixed drum is 
now brought to the desired level, when the clutch is again 
tightened and hoisting proceeds. The change is made in 
2 or 3 minutes. 













































32 


HOISTING, PART 3 


BRAKES 

35. A brake is a device by means of which the motion 
of a hoisting drum may be retarded or stopped. This is 
accomplished by friction of the brake against the circumfer¬ 
ence of the brake wheel. There are three types of brakes, 
known as block brakes, post brakes, and strap brakes. 

36. The Block Brake, —The block brake, Fig. 20, 

consists of one or 
more wooden blocks 
or shoes b attached 
to a lever having a 
fulcrum at d, and 
connected by a rod to 
the lever c. Block 
brakes are objected 
to mainly because 
they throw a greaS. 
load on the journals 
of the drum when 

they are applied; they cannot be relied on when there is a 
heavy load on the drum, and they require the application of 
great force to the lever c for a given braking power. They 
are, however, cheap and easily applied to a drum, and the 
shoe is readily replaced when worn. 

37. The Post Brake.— The post brake, Fig. 21, is 
composed practically of two block brakes applied at two 
places on the drum diametrically opposite each other, thus 
equalizing the pressure on the journals. The blocks are 
generally somewhat longer than in the block brake, or about 
one-quarter of the circumference of the drum on each side. 
In Fig. 21, a is the drum; b are wooden brake blocks; c are 
the posts which in the brake shown are of massive, built-up, 
steel construction; d are the fulcrums on the plates e, which 
plates are adjustable by means of the nuts /; by means of 
these nuts, the fulcrums may be brought closer together as 
the wooden blocks b wear away; g is a tension rod generally 














HOISTING, PART 3 


33 


furnished with a turnbuckle to adjust its length as the wooden 
blocks wear away. Power is applied at the end of the bent 
'ever h , as shown by the arrow. 

The stops i are adjusted so that the blocks b on each side 
ire equally distant from the drum when the brake is off. 



The fulcrums d should be some distance below the drum and 
brake ring, for if they are too near the drum it will be difficult 



to swing the lower end of the wooden blocks far enough to 
clear the drum. 


38. Improved Post Brake. —In order to have an equal 
clearance at top and bottom, and to have a more powerful 































































34 


HOISTING, PART 3 


leverage than in the ordinary post brake, the posts may be 
made movable at both top and bottom, Fig. 22. The tops 
of the posts a a! are moved, as in Fig. 21, by the tension rodb 
and the leverc, the latter being connected by rod d to levers. 
This lever is pivoted at / and motion is transmitted to the 
fulcrums/ by the link^-, the lever h , and the tension rod i. 
The back post a is supported by the uprights k , which are 
pivoted at l and swing backwards and forwards like a parallel 
ruler. The front post a' is supported by the single upright m , 
pivoted at n. The setscrews o regulate the motion of the 
bottom of the posts so as to give equal clearance to the 
bottom and top of the posts. 

An objection to both the block and the post brake is 
the fact that, if the drum surface to which the brake is 
applied is not perfectly round, the resistance of the brake 
will not be uniform when applied while the drum is in 
motion. 


39. The Strap Brake. —A strap brake consists of a 
wrought-iron band or strap that partly encircles the drum and 
is connected at its free ends to levers with which the band 
may be tightened on the brake wheel and the drum thus 
firmly held. The iron or steel band either lies directly 
against the wooden lagging of the drum or on wooden blocks 
bolted to the drum; or else it has bolted to it a lining of 
wooden blocks that bear on the drum when the band is 
tightened. 

The most efficient forms of strap brakes are those in which 
the strap or straps are in contact with 270° or more of the 
circumference of the drum. The greater the arc of contact, 
the more securely is the drum held by the brake. A single 
strap is sometimes used, but this is only satisfactory 
with small drums, say 8 feet or less in diameter;, on large 
drums two straps are generally used, each extending half 
way around the drum. The levers for transmitting the power 
from the hand lever or treadle to the brake strap are vari¬ 
ously arranged. In some cases, the force is multiplied by 
several short levers; in others, by one long lever. The 


HOISTING, PART 3 


35 


treadle or foot-lever, however, has been replaced almost 
entirely by the hand lever. 

40. The simplest form of strap brake, Fig. 23, consists 
of a single strap a , with one end anchored at b and the free 



end attached to the brake lever c. This brake acts on the 
same principle as the block brake and is open to the objec¬ 
tion that it brings an undue load on the journals, but it is 



more efficient and holds the drum more firmly under a heavy 
load than a block brake. 

Block brakes are usually run dry, but in band brakes and 
post brakes with ample surfaces and proper leverage the 
wood may be occasionally slightly oiled with black oil, which 






































36 


HOISTING, PART 3 


greatly adds to the durability of the blocks without unduly 
lessening the power of the brake. 

41. A two-strap brake is shown in Fig. 24. One end of 
each strap a , b is fastened to the pedestal c by either of the 
methods shown in Fig. 24 (a), (b), and (c ). In the method 
shown in Fig. 24 (a) and (b) , the forgings d , d\ drawn out to 
the form of bolts, are riveted to the ends of the straps and 
passed through a casting c that is secured to the foundation. 
The object in giving one bolt to one strap and two bolts to 
the other strap is to allow the straps to pass each other and 
yet have their lines of action intersect. The bolts are fas¬ 
tened to c by four nuts on each bolt, i. e., two principal nuts 
and two locknuts. This gives a means of adjustment in the 
length of the strap to take up the wear. 

A second method of securing or anchoring the back ends of 
the straps is shown at (c ). In this case, a wrought-iron angu¬ 
lar piece is riveted to each strap, and these pieces are passed 
over the bolt e that takes the place of the casting of the for¬ 
mer arrangement. Nuts are used, as shown, to adjust the 
straps for wear. The bolt should be short and stiff, so as to 
be well able to stand up to its work when the drum is moving 
or tending to move in the direction shown by the arrow. 

When the brake is applied, the friction between the brake 
strap and the circumference of the brake wheel produces a 
great strain on the pedestal c, which must be securely 
anchored. 

The front ends of the straps are worked into eyes, as shown 
at /, and by these eyes and suitable pins passing through them 
the ends are fastened to the brake lever g. This lever is 
supported on and rotates about a pin h , so that when the 
braking force is applied at t, in the direction of the arrow, 
the brake lever rotates, pulling down on strap a and up on 
strap b ; and, if the straps are held firmly at the back end, the 
more force that is applied at i the tighter will the drum be 
gripped by a and b. 

The ends of the straps should be brought in as close to the 
drum as is practicable, both front and back, so as to give the 


HOISTING, PART 3 


37 


greatest amount of contact between the drum and the straps 
and to get the best effect from the force applied. The springs j 
are used with straps that are not stiff enough to clear the 
drum when the brake is released. 


42. The rotation of the drum may assist or retard the 
action of the lever in applying the drop brake. For instance, 
if, in Fig. 23, the drum revolves in the direction indicated by 
the arrow, the pull of the drum at the brake strap is in the 
same direction as the pull of the lever when applying the 
brake and the action of the lever is then assisted by the motion 
of the drum. On the other hand, if the drum is revolving in 
the opposite direction, it opposes the action of the lever and 
a greater force must be applied to the lever to overcome this 
opposing pull of the drum. Hence, in the case of strap brakes, 
if possible, that end should be anchored which will cause the 
revolution of the drum to assist the lever in applying the 
brake and throw the strain on the anchor bolt instead of on 
the lever. 


43. If a brake is required to work with the drum running 
in either direction, there are several ways of bringing the 
strain due to the load 
on the anchorage in 
whichever way the 
drum runs. One of 
the simplest of these 
is shown in Fig. 25, 
where a is a drum 
with a strap brake b 
embracing nearly 

the entire circumfer- fig. 25 

ence; c is a lever bar that is attached to the ends of the brake 
strap by pins d and e , which work in the slots / in the iron 
anchor plates g. One anchor plate is on each side of the 
lever, and both are bolted to the foundation. If the band is 
kept of the proper length, then, no matter which way the drum 
is turning, the pull of the drum will come on the anchorage, 
and the pull on the lever need be only sufficient to take up 









38 


HOISTING, PART 3 


the slack end of the band. To illustrate: If the drum is 
turning in the direction indicated by the arrow, the pin 
e holding the lower end of the band will be on the bottom 
of its slot and the pin cL will be free in its slot and engaged 
in tightening the slack end of the band through the motion of 
the lever c. Were the drum running the other way, the pin d 
connected with the upper half of the band would move to the 
upper end of its slot and take the main load, while the pin e 
at the lower end of the band would only have to take up the 
slack. The outer, or long, end of the lever moves down¬ 
wards in all cases to tighten the band. Provision must be 
made to lift the band clear of the drum when slack, but no 
anchorage other than at^ should be attempted. 

44. Tlie Differential Brake. —The differential brake 
has both ends of the brake strap attached to short lever arms 
operated by the brake lever, but these arms are of different 
lengths and are so arranged that as the longer arm tightens 



the brake strap the shorter arm yields and loosens the strap. 
The tightening, however, is more than the loosening or 
yielding and, as a result, the brake band is tightened about 
the brake wheel. The form of the lever arm is immaterial 
so long as the differential principle is retained, that is, that 
the shorter arm yields when the longer pulls, when the brake 
is thrown into action. This principle is illustrated in Fig. 26. 
In this brake, no provision is made for anchoring either end 
of the brake strap, but the entire load is thrown on the lever 
arms a and b. These lever .arms are connected with the 











HOISTING, PART 3 


39 


arm c , which revolves on the same shaft d and is operated by 
the reach rod e. The revolution of the drum is thus resisted 
by the shaft d. 

This brake is self-acting when the drum revolves so as to 
pull on the shorter arm, as indicated by the arrows; that 
is, the motion of the drum helps to set the brake when the 
latter is once applied. When, however, the drum revolves 
in the opposite direction, the action of the brake is opposed, 
instead of being assisted, by the motion of the drum. As a 
consequence, this particular form of brake is not adapted to 
hoisting drums that revolve in opposite directions at each 
alternate hoist. Differential brakes are not generally used. 

45 . Power for Brakes. —For small drums and light 
loads, the brakes are usually applied by hand power through 
suitable lever connections. The force that a man can exert 
can be multiplied indefinitely by levers and combinations of 
levers; but while the force is multiplied, the distance through 



which it can act is divided in the same ratio. A certain 
amount of motion is required to free the brake band from 
the drum, when the brake is off; this, then, limits the lever¬ 
age that a man can use. Suppose, for instance, that with a 
strap brake the band moves from the drum i inch, thus 
increasing the diameter 1 inch, or the circumference about 
3 inches. Then, supposing that a man can exert his force to 
advantage through 3 feet, or 36 inches, the available lever¬ 
age is ¥- = 12. That is, if a man can pull 50 pounds on his 















40 


HOISTING, PART 3 


hand lever, he can exert 50 X 12 = 600 pounds circumferen¬ 
tially on the brake band, with simple levers. If any form of 
differential levers is used, the ratio by which the force 
applied at the hand lever can be increased will be consid¬ 
erably larger. A diagram will explain this more clearly. 

46 . In Fig. 27, a is the hand lever, with a fulcrum at b 
and a pin at c by which it takes hold of a reach rod or con¬ 
nection d. This rod is connected to the end h of the brake 
lever e , which is connected by pins at f,g to the brake bands. 
If the leverage of the hand lever a is made 6 to 1, that is, if 

and a force of 50 pounds is applied at a, a pull of 

300 pounds will be exerted at the pin c and, consequently, 
along the rod d to the end of the brake lever e. Then, if the 

brake lever is made with a ratio of 4 to 1, that is, if — = - 

eh €g 1 

= 77 ’ a pounds X 4 = 1,200 pounds will be exerted 

at the pin / or g. This total pull must be divided equally 

between the arms eg and <?/, giving 600 pounds pull on each. 
According to the principle of the lever, the distances through 
which these forces act are inversely proportional to the forces 
acting. It is assumed that the brakeman can exert the force of 
50 pounds through 36 inches; if this is the motion of the end 
of the hand lever a, one-sixth of this, or 6 inches, will be the 
motion at c and, therefore, at h; one-fourth of 6 inches or 
li inches will be the motion at / and g; that is, / will 
increase its half of the brake band inches in circum¬ 
ference, and g will do likewise with its half, making the total 
circumference 3 inches more, or the diameter 1 inch more, 
and thereby moving the band away from the drum i inch 
radially. The levers are all shown in mid-position to make 
the figure more simple, but the relative leverages remain the 
same at all points in the motion. 

This is an example of simple levers, but the force applied 
at the hand lever may be increased in a much greater ratio 
by the use of a device known as a differential lever . 


HOISTING, PART 3 


41 


, 47. The Differential Lever.—The principle of the 
operation of the differential lever with which a constantly 
increasing force can be applied to the brake strap is illustrated 
in Fig. 28. Let ao represent a straight lever whose fulcrum 


a 



Fig. 28 


is at o\ and let the reach rod be attached at e. In this posi- 

0 

tion, if — * the effective lever is 6 to 1. If, now, the 
eo 1 

lever is moved through 30° to the position bo, the force 
applied at a moves through the distance a b, and the reach rod 
through the horizontal distance kf, so that the effective lever¬ 
age is increased a small amount ek and the ratio of the arms 

becomes —. When the lever is moved another 30° to the 
ko 

position co, the reach rod moves a distance ig, which is less 
than kf, so that the effective leverage is increased by the 

amount kl and the ratio of the arms becomes a -°. Again, 

lo 

moving the lever 30° more to the position do, the reach 
rod moves through the still shorter distance jh, which is less 
than ig, and the effective leverage becomes very great. It 
is evident from this that the farther the lever is moved 
toward d the greater becomes the effective leverage In 






42 


HOISTING, PART 3 


practice, it would be impossible to move the lever through the 
entire quadrant to advantage, and there would also be more 
movement of the reach rod at the beginning of the stroke and 
less at the end than is needed to produce the desired effect. 

From the principle just given, it is plain that, if po , Fig. 28, 
represents a brake lever with the reach rod attached at q , a 
smaller pull will be exerted on the brake band if the lever is 

s moved to the position b o 
fl) than would be exerted if 

ft' 

ill a lever were moved 
through the same angle 
from bo to do. The 
movement from po to bo 
is a convenient and easy 
one for the engineer to 
make, while the move¬ 
ment from bo to do is 
inconvenient. To over¬ 
come the inconvenience 
and still to obtain the 
advantage of this latter 
movement, the differ¬ 
ential lever shown in 
Fig. 29 is used. By 
means of an arm placed 
on the lever, the point 
of attaching the reach 
rod is at l instead of p\ 
hence, when the handle rb is moved to the position sb, the 
point l moves to m , thus securing a greater and gradually 
increasing pull with the easier movement of the handle. 

A differential lever may be advantageously used in connec¬ 
tion with any band or post brake and on a drum running in 
either direction. Such levers are considered by many pref¬ 
erable to the differential brake. 

48. Power Brakes.—Large drums and heavily loaded 
drums cannot be controlled by hand-power brakes, and in such 



Fig. 29 







HOISTING, PART 3 


43 


a case some other form of power, such as steam, compressed 
air, or water, must be used. 

Fig. 30 shows, in outline, how such power is applied. The 
movements of the hand lever A , instead of being directly 
communicated to the lever operating the brake, merely con¬ 
trol the valve v connected with the cylinder a. By means 
of this valve, steam, compressed air, or water is admitted to 
either end of the cylinder and this moves the piston in the 
direction necessary to apply or release the brake. There are 
a number of varieties of such power brakes, differing in 
structural details, but the action of all is essentially the same. 
With steam or air power, the brake would be applied with its 



full force almost instantaneously, thus subjecting the various 
parts of the mechanism to very severe and objectionable 
strains, unless the valves were modified so as to regulate the 
admission of the steam or air. One method of controlling 
this action is the use of a valve that requires a long travel to 
give it a full opening. Such a valve can be opened a little, 
so as to allow the steam to leak through and thereby increase 
the pressure in the cylinder gradually. As the motion is 
difficult to regulate, a better method is by means of a float¬ 
ing valve, described in Hoisting , Part 1. 

49. Crank-Brake.—In addition to the brake applied to 
the drum and intended for use mainly in emergencies, many 
hoisting engines are also fitted with a strap brake applied to 
the crank-disk. In some states, crank-brakes are required 
by law. In order to give a large bearing surface, the crank 
disk is made very large. 

















HOISTING 

(PART 4) 


Serial 851D _ Edition 1 

HOISTING APPLIANCES 


SHEAVES 

1. Sheaves are grooved iron or steel wheels used to 
carry or guide a rope. The general method of mounting 
them on a frame foi 
hoisting light loads is 
shown in Fig. 1. The 
journal boxes are so 
constructed as to be 
easily taken apart for 
inspection or repair. 

For hoisting heavy 
loads, the timbers 
must be braced, as is 
explained under the 
heading Head- 
Frames in this Sec¬ 
tion. Sheaves are of 
two styles—those 
composed entirely of 
cast iron and those 
with cast-iron hubs and rims and wrought-iron or soft-steel 
arms or spokes. 

2. The cast-iron sheave, Fig. 2, has arms with a cross- 
section, as shown at a b, and with the flanges of the arms 

COPYRIGHTED BY INTERNATIONAL TEXTBOOK COMPANY. ALL RIGHTS RESERVED 



447—4 































2 


HOISTING. PART 4 


tapering from the hub to the rim; that is, d is greater than c 
and / is greater than e. The bottom of the groove g in the 
rim should be a circular arc, whose radius is a little larger 
than that of the rope used over the sheave, to allow for the 
angling of the rope due to its fleeting on the drum. The 
flanges h are made quite deep to prevent the rope jumping off. 

This sheave is cheaper than a combined cast-iron and 
wrought-iron or steel sheave, and for many purposes it is 
entirely satisfactory. Its great weight is an objection, 



considerable resistance to being set in motion and stopped. 

If a sheave is merely used to carry the rope or to deflect 
it only a little, the contact and pressure between the rope and 
the sheave is small; consequently, the power of the rope to 
turn the sheave will be slight. In such a case, when the 
rope starts or stops quickly, as it usually does in modern 
hoisting plants, the heavier the sheave the more will it lag 
behind the rope and the greater will be the wear on the rope 
due to slipping. 

3. The sheave with a cast-iron hub and rim and wrought- 
iron or soft-steel spokes, Fig. 3, is an excellent and exten¬ 
sively used sheave, especially the larger diameters. The 



























HOISTING, PART 4 


3 


spokes are screwed into the hub and rim and are carried to 
the right and to the left of the hub alternately, as shown 
in Fig. 3 (b), so as to take hold of the opposite ends of the 
hub, thereby giving stiffness to the sheave against any side 
stress. 

With a sheave having cast-iron arms, the load from the 
rope is transmitted to the shaft by a compressive stress 
through the arms directly under the load; that is, if a rope 
runs over the sheave, Fig. 2, putting a load on it from j to k, 



this load will be transmitted as a compressive stress through 
the arms / and m to the hub and the shaft. Of course, a 
part of this load is carried around the rim to the lower arms 
and is supported by them in tension, but these lower arms 
are not considered in designing the sheave because cast iron 
is of comparatively little value in tension, whereas it is of 
great value in compression. In the case of the sheave with 
wrought-iron arms, or spokes, Fig. 3, the load is transmitted 
around the rim to the side opposite its point of application 
and is carried from there to the hub and shaft by the tension 
of the spokes; in fact, from the method of construction, the 
spokes in this sheave act only by tension. The sheave is 
strong and rigid, and much lighter than a cast-iron sheave 




















4 


HOISTING, PART 4 


of the same strength, so that there is less wear between it 
and the rope due to any slipping action when it is started or 
stopped. 

4. Sometimes, the spokes, instead of being radial as in 
Fig. 3, are made tangent at the center of the wheel, Fig. 4, 

to an imaginary circle, 
which is about 2 inches 
in diameter for a 10- 
foot sheave. Alternate 
pairs of spokes are 
made tangent to the 
opposite sides of the 
circle, so that they pull 
against each other, and 
this makes the sheave 
rigid in both directions. 
That is, spoke A is 
tangent to the right 
side of the tangent cir¬ 
cle and A' to the left 
side, while spoke B is tangent to the right side of the circle 
and B' to the left side. The pair B B' is joined to one end 
of the hub, while the pair A A' is joined to 
the other end, thus giving lateral stiffness 
to the sheave. This arranges the spokes 
in groups of four, so that the total number 
must be some multiple of four. The tan¬ 
gential direction of the spokes is often 
necessary in very large sheaves carrying 
heavy loads, because with such a sheave 
it requires considerable force to turn the 
shaft in its bearings, and while radial 
spokes act only as long levers in turning 
the shaft, with tangential spokes there is also a direct pull 
to do it. 

5. Wood-Lined Sheaves.—The rims of all sheaves are 
made either solid or with wooden lining, as shown in section 
































HOISTING, PART 4 


5 


in Fig. 5. One flange a of the rim is a separate piece that is 
held on by bolts b. The wooden lining is in the form of 
blocks placed with the grain of the wood running radially 
and held securely by clamping together the two flanges with 
bolts, as shown. With such a sheave, there is much less 
wear on the rope than there is with one that has a plain cast- 
iron rim. The wear of the sheave proper is also avoided, 
because as the blocks wear down they are taken out and 
replaced by new ones. 

6. Diameter of Slieave. —The size of a sheave about 
which a rope bends is determined generally by the size of 
the rope to be used, as explained under Wire Ropes in 
Hoisting , Part 2; but, if the rope is simply to be supported 
in a straight line, the space available for setting the sheave 
and its cost and weight usually determine the size used. 
The minimum allowable diameter of sheave should not be 
used unless it is necessary to do so, for the larger the sheave 
the less will be the wear of the rope due to the bending, 
and the longer the life of. the rope, but the cost of the 
sheave, which increases with the size, puts a limit in the 
other direction. 

7. Rollers and Carrying Sheaves. —Wooden or iron 
rollers are sometimes used for rope carriers or guides, instead 
of light sheaves, when the rope has merely to be supported 
and there is no bending of the rope, excepting the slight 
amount due to the sagging between the rollers. The diame¬ 
ter of the rollers is of little importance in such cases so far 
as the rope is concerned. If they are for use on a slope to 
keep the rope from dragging on the ground, they must be 
small, because the cars must run over them, and mine cars 
are usually made low because of restricted headroom in the 
mine. Rollers and carrying sheaves are fully described and 
illustrated in Hatilage. 

If a hoisting rope changes its course from a straight line, 
even if the deflection is only a small amount, a roller is not 
advisable and a sheave should be used, if possible. 


6 


HOISTING, PART 4 


CAGES 


CAGES FOR VERTICAL SHAFTS 

8. A cage is a carriage used for hoisting mine cars and 
their contents, men, timber, etc., in both vertical and inclined 



shafts. Cages are built of wood strengthened with iron or 
steel, or entirely of iron or steel. 

9. The cage shown in Fig. 6 is much used in the anthra¬ 
cite region of Pennsylvania. It is made largely of oak 
strengthened with iron and the size varies to suit the shaft. 





















































HOISTING, PART 4 


7 


being- sometimes as large as 6 feet wide by 12 feet long. 
The general construction of the cage is evident from the 
figure, but several appliances that should be common to all 
cages in some form or other require detailed explanation. 

A covering a , called a bonnet, protects persons on the 
cage from objects falling down the shaft, and is required by 
law in some States. This bonnet is made of steel plate 
with flanges or angle irons to stiffen it, and is usually 
inclined. To prevent objects of moderate size from wedging 
between the edge of the bonnet and the shaft lining, the 
former is sometimes made shorter than the cage, so that a 
space of about a foot is left between its lower edge and the 
shaft lining. A short bonnet of this character does not, 
however, fully protect persons on the cage. The upper 
part of the bonnet is fastened to the upper cross-bar of the 
cage by two hinges and is held up by rods b that are 
attached to the bonnet and have sockets at their lower ends, 
which fit over pins bolted to the uprights of the cage. By 
raising the rods from the pins the bonnet can be lowered 
so that pipes or long timbers may be lowered on the cage. 

10. Safety catches are intended to prevent a cage fall¬ 
ing in case the hoisting rope breaks. A common form, 
shown at c. Fig. 6, and in detail in Fig. 7, consists of a pair 
of toothed cams /, Fig. 7, fastened on each side of the cage 
near the shaft guides. The drawbar b to which the rope is 
attached extends through the top cross-piece of the cage and 
through the cylinder d , at the bottom of which is a plate c 
supplied with lugs for the rods / that connect it with the 
levers g. Inside the cylinder are three powerful rubber 
springs, which are in compression so long as the cage hangs 
from the rope, but are extended if the rope breaks, draw¬ 
ing the rods / down and with them the ends of the levers^ 
to which they are attached; and, since the levers are pivoted, 
their other ends are moved upwards and with them the 
rods k. The cams j are each attached to one end of the rods 
k in such a manner that as the rods move upwards they rotate 
the cams inwards until they come in contact with the shaft 


8 


HOISTING, PART 4 


guides. The teeth of the cams grasp the wooden shaft guides 
and stop the descent of the cage. The cams are provided with 
projections a and l that strike the guide and thus prevent the 
cams turning entirely around. Fig. 7 (a) shows the springs 
extended and the dogs j just about to grasp the shaft guides, 
while Fig. 7 ( c ) shows the position of the dogs when the 
springs are compressed as they are when hoisting. At e in 
cylinder d, Fig. 7 (b), there are slots for the lugs of plate c 
to move up and down as the spring is compressed or 



extended. Instead of rubber springs, helical steel springs 
are sometimes used, and with a somewhat different design 
flat steel springs are used. 

The cams, or dogs, may be placed at any point along the 
upright post of the cage, and in some cases two sets of cams 
are used on each side, one set at the top and another in the 
middle, both sets being connected by rods so that they work 
together. Practical tests of these catches, made by allowing 
the cage to drop, show that they are, as a rule, very efficient 
devices. The cams usually take hold at once, the cage 
dropping only a few inches,.or, at most, a few feet if the 

























































HOISTING, PART 4 


9 


guides are dry and free from oil. When the guides are very 
greasy or wet, the cage may drop several feet before the 



cams take a firm hold and stop it, and with ice-covered 
guides, instances are given where the cage has fallen 15 feet 
before the cams ploughed their way through the ice and took 
































































10 


HOISTING, PART 4 


firm hold of the guides; but in so doing the momentum the 
cage acquired was so great that the guides were destroyed. 
Fortunately for the utility of safety catches, ropes are usually 
broken while a loaded cage is being raised, and the cage has 
an upward momentum; if a rope breaks when the cage is 
descending at a speed of 30 or 40 feet a second, its momen¬ 
tum is so great that either the catches or guides break. 
The catches generally hold and either the guides or cage 
suffer more or less injury under such circumstances. Instead 
of being placed near the top of the cage the dogs are fre¬ 
quently placed near the center, or near the bottom; in some 
cases two sets of dogs have been used, one set being at the 
top and the other at the bottom. Instead of being cam¬ 
shaped with a number of small teeth on the rim of the cam, 
as shown in Fig. 7, the dogs are now frequently made con¬ 
sisting of one or more strong straight teeth on each side of the 
guide. These teeth are operated similarly to those shown 
in Fig. 7, and are driven into the guides if the rope breaks, 
thus holding the cage more firmly than the cam-shaped 
guides, particularly where the guides are wet. 


TABLE I 


Platform 


Guides 




Width 

Length 

Size 

Distance Between 

Safe Load 
Pounds 

Weight 

Pounds 

Feet 

Inches 

Feet 

Inches 

Feet 

Inches 



4 

6 

3 

6 

10 

6X6 
6 X io 

4 

6 

6 

3 

5,000 

8,ooo 

2,000 

3,8oo 


11. The Heavy Steel Cage.—The cage that is shown in 
Fig. 8 is made of iron and steel except the wood flooring, which 
is laid in two courses, one lengthwise and one diagonal. The 
joints should not be driven too tightly, as the wood is likely 
to swell. The track is bolted to the floor, or deck, of the 
cage. The cast-steel safety dogs are operated by steel 
springs a , coiled about the bars b, which are connected to the 

























HOISTING, PART 4 


11 


drawbar c by chains, as shown. The drawbar drops if the 
rope breaks and thus assists the action of the springs a. 
This cage is in use at both coal and iron mines, and is built 
to suit any size of 
shaft and guides. 

Standard sizes are 
given in Table I. 

12. The Tight 
Steel Cage. —Fig. 9 
shows a light steel 
cage much used at 
gold and silver mines. 

It has a spring draw¬ 
bar and steel safety 
dogs, operated by 
steel springs, as in 
Fig. 8, but the floor 
is of steel grating in 
order to give as little 
air pressure as pos¬ 
sible against the 
cage. The openings 
a in the side frames 
are provided so that 
through them the 
nuts can be tightened 
on the bolts that hold 
the shaft guides. The 
cage is provided 
with bails b that 
swing down over each end of a car to hold it on the cage. 

13. Multiple-Deck Cages.— Cages are sometimes built 
that have two or more decks or platforms one above the 
other, thus giving greater hoisting capacity to a shaft. A 
two-deck, safety, hoisting cage is shown in Fig. 10. The 
upper deck is heavier than in a single-deck cage of similar con¬ 
struction. The lower deck is suspended from the upper deck 

































12 


HOISTING, PART 4 



by means of pins so that it 
may be removed at any 
time. A double-deck cage 
may be used by first chang¬ 
ing the car on the upper 
deck and then bringing the 
lower deck to the track 
level and changing the 
other car. Time can be 
saved by having two track 
levels, both at the loading 
and landing stations, ena¬ 
bling both decks to be 
loaded and unloaded at 
the same time. 

Multiple-deck cages 
have been mainly used at 
ore mines in America and 
very few coal mines have 
been equipped with them. 
Cages are also built to ac¬ 
commodate two cars placed 
either side by side or end 
to end. 


AUTOMATIC DUMPING 
CAGES 

14. A dumping cage 

is a cage so constructed 
that at the proper place it 
can be automatically tip¬ 
ped sufficiently to dump 
the contents of a car that 
is on it and will then right 
itself for the down trip, 
thus avoiding the necessity 
of removing the car from 
































HOISTING, PART 4 


13 



the cage, and saving 
time at the head. 
The construction of 
the cage is such that 
the car is held firmly 
in place while dump¬ 
ing. The principle of 
the self-dumping 
cage is illustrated in 
Fig. 11, the cage 
being shown in its 
highest and lowest 
positions. The cage 
is made in two parts a 
and b. The fixed 
frames b slide on the 
guides k and have 
attached to them the 
safety catches and 
hoisting gear. The 
movable part a is 
united to the frame b 
by the hinge c. The 
platform d, on which 
the car rests, is fast¬ 
ened to the movable 
part a by the support 
e and further secured 
by the braces /. At 
the top of a is at¬ 
tached the wheel g 
that runs along the 
rail h } keeping a in an 
upright position until 
it reaches the dump¬ 
ing place i. Here the 
rail h is bent as shown 
and the wheel g is 


Fig. 11 
















































































14 


HOISTING, PART 4 


made to follow it by means of the guide j. This throws the 
top of a over so as to incline the platform and dump the car 
that is on it. On lowering, the cage rights itself when g 
passes below the point i. The part b is kept in a vertical 
position by means of shoes that slide on the main guides k. 

It is possible to dispense with the guide rail h by attaching 
a flange to the top of a at the back, to slide on the main 
guide k. This flange should be shorter than the shoe on b. 
The main guide is cut away at the point where this flange 
comes when the wheel g enters the curved guide /, leaving an 
opening just large enough to allow the flange on a to pass 
through. The shoe on b , being longer, completely spans the 
space and cannot pass through, but makes b move straight up 
on the main guides. 

The bottom of the cage in Fig. 11 has an interrupted track, 
and at the bottom of the shaft the track is also interrupted, as 
shown in the plan at the bottom of the figure, but in such a 
way that when the cage is resting at the bottom this portion 
of the track n projects up through the bottom of the cage 
and makes a continuous track. When the cage is raised the 
wheels of the car drop into the spaces n in the cage bottom, 
thus preventing the car from running off the cage during 
hoisting or dumping. 

15. Slope, or Inclined-Shaft, Hoisting. —In a slope, 
or inclined shaft, the mine cars are attached directly to the 
hoisting rope and hoisted singly or in trains for inclinations 
less than 35°, at which inclination the material will begin 
to fall from the top of the car. For steeper slopes, it is 
customary to use a slope cage or carriage on which the 
mine car is hoisted, or else to dump one or more cars of the 
material into a gunboat, or skip, at the bottom of the slope or 
at some landing along the slope, and to then hoist the gun¬ 
boat, or skip. 

Fig. 12 shows a cage for use in a slope or steeply inclined 
shaft. It is made of steel with timber platform and differs 
from a vertical shaft cage mainly in having its upper frame 
inclined and in running on four wheels a , b. These wheels 


HOISTING, PART 4 


15 


usually run on timber guides, so that the safety dogs c will 
take hold of the guide in case the rope breaks. For slopes 
of variable inclination, the platform d may be made adjust¬ 
able by means of a hand lever so as to be always level. 

16. A slope carriage is a frame so constructed that 



when rails are placed on the top and a mine car run on 
them the car will be practically horizontal. The carriage is 
mounted on wheels and axles in order to follow the slope 
tracks, and is supplied with a drawbar, or with hooks, as 
shown in Fig. 13, for attachment to the hoisting rope. 




16 


HOISTING, PART 4 


These carriages are sometimes built to run on a slope 
track of the same gauge as the mine cars, but to insure 
stability they have generally a broader gauge. The head- 
room necessary is governed not so much by the form of the 
carriage as by the length of the car and the inclination of 
the seam. This height is less when the cars are placed 
on the carriage with their length across the slope than when 
they are run on lengthwise; but this arrangement increases 
the width of the slope. When the inclination is very steep, 



Fig.13 


the wheels are sometimes placed on the sides of the carriage 
and above its center of gravity and run between two tracks 
or guides, on each side of the slope. 

The carriage, Fig. 13, is for use on slopes of a uniform incli¬ 
nation. It is made almost entirely of heavy timber, is stiff and 
simple of construction, and is easy to repair. Its details will 
be readily understood from the illustrations, except perhaps, 
the device for locking the car to prevent its running off 
during the hoist. The middle portion of the platform a 
having a piece of the car track on it, may move vertically 












































HOISTING, PART 4 


17 


up or down. As shown in the side elevation, it is resting 
on the horizontal timbers b of the carriage in a position ready 
for hoisting. At the end of the hoist, when the cage 
settles on the keeps c, shown in the end elevation, this plat¬ 
form reaches them first and is supported by them while the 
rest of the carriage descends still farther until the timbers d 
rest on the keeps also. The track on the platform a is then 
at the same level as that on d , and the car can be run off 
and replaced by another. When the empty car is on, the 
carriage is lifted from the keeps, but the platform a remains 
until the timbers b pick it up, when the keeps are swung 
back out of the way and the carriage is lowered. 

Slope carriages usually have the tracks running crosswise 
so that the car is pushed on from the side instead of from 
the end. 


SKIPS, OK GUNBOATS 

17. Skips are self-dumping cars used for hoisting 
material from shafts or slopes. In a vertical shaft, they run 
in guide tracks; but in a slope they have wheels and run on 
a track like a car. In the anthracite region of Pennsylvania, 
skips are called gunboats. 

As the skip is not detached from the hoisting rope, time is 
saved at the top over that needed to unhook and hook the 
cars to the rope or to remove and place the cars on the cage. 
But since dumping the material into the skip and again on 
the surface produces considerable fine material, skips, or gun¬ 
boats, are seldom used for any material, such as coal, that is 
often lessened in value by being broken. The skip, or gun¬ 
boat, shown in Fig. 14 is closed along the top a and open at 
the end b , which is cut at about the angle of the slope in which 
it is to be used, so as to remain practically level during the 
hoist. It is made of sheet iron, the bottom, sides, and top 
being stiffened by angle or T irons, and the back stiffened 
and protected by 3-inch planks, backed by 3" X 6" timbers. 
The wheels of a skip are fixed on the axles, which run 
in journal boxes, thus insuring smoother running than is 
obtained with loose wheels. The details of the journal 


447—5 



18 


HOISTING, PART 4 



bearings, as shown in Fig. 15, consist of three castings, the 


bracket a , which is bolted or riveted to the gunboat, a pivot 

casting b , and the 
bearing proper c. 
The bearing c rests 
on the axle and car¬ 
ries, by means of 
trunnions d ,, the pivot 
casting b , on the top 
of which is placed a 
rubber cushion e to 
lessen the shocks 
between the casting 
and the bracket. 

18. Method of 
Fig - 15 Loading Skips. —In 

Fig. 16, a skip a is shown in a slope standing immediately 




__ v jf 

b 

r 

llo 

a 

ojfa 



go 

wmm< 



















































HOISTING, PART 4 


19 


below a level where a car b is ready to have its load dumped 
into the skip. Instead of dumping the mine car directly into 
the skip, a bin is fre¬ 


quently provided at the 
level station, or landing, 
into which the mine cars 
are dumped and from 
which the material is 
loaded into the skip 
through suitable chutes. 
The use of such bins 
makes the hoisting of 
material largely inde¬ 
pendent of the working 
conditions on the levels 
and the hoisting can 



be more systematically and satisfactorily carried on. 

If the material comes to the slope as shown in Fig. 17, it 

is necessary to let 
down a bridge a , on 
which the car runs, in 
order to reach the 
skip. After the car is 
dumped, the bridge is 
lifted out of the way 
into the dotted posi¬ 
tion, so as to leave the 
slope unobstructed. 

19. Method of 
Dumping Skips. 
To dump a skip at the 
surface, the tracks 
are extended above 
the slope mouth, as 
shown in Figs. 18 and 
19, and are arranged so that the material may be dumped 
directly into a bin or into cars as desired. 



Fig. 17 












20 


HOISTING, PART 4 


In the arrangement shown in Fig. 18, the front wheel of 
the skip strikes a stop a and,, since the bail of the skip is 
pivoted far down toward the lower end, as the rope continues 
to pull, the rear of the skip is raised and the material is 
dumped. The objection to this method is that if the rope is 
slightly overwound the skip is pulled off the track and does 
not then right itself on the track when the rope is released. 



In the Lake Superior iron and copper region, many of the 
dumps are built as shown in Fig. 19. In this dump, the rails 
of the main track a are curved as shown at b\ a short 
distance back of the beginning of this curve, another track c 
begins outside the track a and runs in a straight line parallel 
to the inclination of the hoist. The track c is of a wider 
gauge than a , and the rear wheels of the skip have a wider 
tread than the front, so that they will run on c while the front 



















































HOISTING, PART 4 




Fig. Hi 


♦ 



























































22 


HOISTING, PART 4 


/V 


























































HOISTING, PART 4 


23 


wheels take the curved track until they strike the stop d. 
The rear of the skip will thus be raised and the material 
dumped. There are but two tracks in the main part of 
the slope. 

In the method illustrated in Fig. 20, the rear and front 
wheels have the same tread, but the rear axle is longer than 
the front and has rollers a on each side. These strike the 
track b , and while the front wheels follow the curved track c 
these rollers run on the track b and thus raise the rear end 
of the skip. 

20. Skip Cage. —Where a self-dumping skip is to be 
used in a vertical or highly inclined shaft and it is desired 
to use safety catches, the skip a is mounted in a cage or 
frame b } Fig. 21, similar to the self-dumping cage, Fig. 11. 
The skip being pivoted at c one side of the center, and 
resting on the frame of the cage, tends to remain upright 
until it reaches the dump; but for safety it is sometimes 
locked in place by the latch d , which hooks over the pin e. 
When near the top, the roller / on the end of the latch d 
comes in contact with a bar that depresses the roller and 
thus unhooks the latch. The roller g enters and travels 
along the guide rails h , tipping the skip. There are two 
rollers g } one on either side of the skip. The nose i is 
temporarily caught on the roller /, thus stopping the move¬ 
ment of the skip sidewise and away from the upright guide. 


BUCKETS 

21. Buckets, such as are used for hoisting material 
during shaft sinking, are continued in use after mining 
begins when the amount of material to be hoisted is small. 


CAR LOCKS 

22. Several methods of keeping the car on the cage have 
already been illustrated: by chains, Fig. 8; by bails, Figs. 9, 
10, and 12; by omitting sections of the rail under the car 
wheels, Fig. 11; and by dropping a portion of the platform, 




24 


HOISTING, PART 4 


Fig. 13. A very common way is merely to put a pin through 
the hole in the drawbar and into the floor of the cage. 
Another common device consists of a brake block that fits 

between the wheels 
and can be thrown in 
from the side by a 
lever when the car is 
in place. Another 
device consists of a 
yoke, which, by means 
of a lever, is raised 
when the car is in 
place so that it passes 
about the axle and 
thus holds the car. 
A device frequently 
used on self-dumping 
cages is shown in 
Fig. 22. 

The curved bars a 
of iron, which just fit 
around the car wheels 
as shown, are at¬ 
tached to the loose 
bars b , on the ends 
of which are the 
weights c. When the 
cage is at the bottom, 
these weights strike 
on a cross-piece and 
are raised to the posi¬ 
tion shown by the 
dotted lines, throw¬ 
ing out the bars b , as shown by the dotted line, thus releas¬ 
ing the wheels. The devices shown in Figs. 11, 13, and 22 
do not come into action until the cage leaves the landing 
and the cars must, therefore, be watched until that time. 


























































HOISTING, PART 4 


25 


CAGE GUIDES 

23. Guides are used in all vertical shafts of any con¬ 
siderable depth and in many highly inclined shafts to keep 
the cage from swinging about and striking the sides of the 
shaft. They are made of wooden rails, iron rails, or wire 
ropes. In American mines, timber guides predominate, 
although some iron ones are used, and for small shafts at 
ore mines wire-rope guides are common. In English mines, 
wire ropes, called conductors , are very largely used. This 
difference in practice is probably due to the fact that in 
English mines the shafts are usually round and the cages 
are rectangular. In such a shaft, the wire-rope conductors 
hang from the head-frame without any cross-bracing, but 
they require a strong support, as both the weight of the ropes 
and the strain to give the 
necessary tension come on 
the head-frame. When 
both the shaft and the cage 
are rectangular, as in most 
American mines, timber 
guides are easily put in 
and they offer a good sur¬ 
face for the safety catches 
to grip. 

Wooden guides are 
always rectangular in fig. 23 

cross-section and in the United States are usually made of 
yellow pine or other long-grained wood that does not splinter 
easily; in some localities, oak or some of the other harder 
woods are used. There is no fixed size for cage guides, but 
4" X 4", 6" X 8", 8" X 10", and 4i" X 11" timbers are fre¬ 
quently used. 

The guides are firmly fastened to the shaft buntons with 
lagscrews or with bolts countersunk into the guide so as to 
be clear of the shoes, and, to secure safety with speed in 
hoisting, the ends of the guides must be put together with 
joints that are not liable to displacement and that offer no 










26 


HOISTING, PART 4 


projections to the shoes in passing. The buntons to which 
the guides are secured must be so firmly fastened that they 
cannot get out of place, and the guides must be set as nearly 
as possible in a straight line, because if they are crooked 
the cage is thrown back and forth as it travels along them and 
this not only increases the strain on the hoisting rope and 
engine, but sooner or later loosens and misplaces the guide. 
Fig. 23 shows a plan of a cage with the bunton A , guides B } 
and cage shoes C in their normal positions. 


LANDING FANS OR KEEPS 

24. In order to take the strain off the hoisting rope 
while a cage or skip is being loaded or unloaded, a mecha¬ 
nism to support the cage is placed at the top and at any level 
of the mine where loading is done, excepting at the bottom 
level where all that is usually required are the cross-timbers 
for the cage to rest on. These supports have different 
names in various localities, being known as fans, keeps , cage 
rests , landing dogs , landing chairs, wings , etc. Their use 
increases the safety of caging. 

25. A common form of keeps is shown in Fig. 24. The 
cage a rests on four square bars of iron b, one under each 
corner of the cage. These bars have an eye or hub at the 
lower end and are keyed to the shafts d, which rest in cast 
steel boxes. The levers e and /, which are also keyed to the 
ends of the shafts d , are connected by a rod g. Chains h 
prevent the fans from moving too far under the cage. When 
the cage is to be lowered, it is first lifted clear of the fans and 
the lever ^ is moved into the dotted position, thus moving the 
fans b out of the way and permitting the cage to be lowered. 
The inside of the fans have no projections, and the operating 
mechanism is such that no harm would come if they were 
left in the shaft and a hoist were made, as the cage would 
open out the fans and pass through them without any trouble. 
If, however, the fans are not drawn back at all the headings 
in the shaft when the cage is lowered, great damage results 
when the cage strikes the projecting fans. To avoid the 



HOISTING, PART 4 


27 


possibility of such an accident, fans have been devised that 
fall back out of line of the shaft as soon as the weight of the 
cage is removed from them. 

26. Hydrostatic Fans. —Most fans in use are built on 
the same principle as those just described, although the 
details of their construction may vary. An objection that 



can be raised against them is that, with large cages and 
heavy loads, the jar caused by letting the cage down on such 
a rigid support is very hard on the cage. All cages, particu¬ 
larly heavy ones, suffer much more wear from being landed 
too suddenly than from the strains of hoisting. For this 
reason, it is advisable to make the upper parts as light as com¬ 
patible with strength and the side pieces stronger than needed 
for the actual strains to which they are subjected. Hydrau¬ 
lic fans, Fig. 25, have successfully overcome this trouble. 




















28 


HOISTING, PART 4 


The cylinder shown is one of four on which the cage rests. 
The eye at the lower end fits on a bar by means of which the 
cylinders are moved backwards and forwards similar to the 
motion of the fans b , Fig. 24. In Fig. 25 ( a ), the cage is 
shown as about to rest on the jaw a . As the cage settles, it 
pushes the plunger b downwards, but this action is resisted 
by oil in the cylinder at c. At first, this resistance is very 
slight, because the V-shaped grooves d in the plunger, which 
are of considerable size at the end of the plunger, allow the 



oil to escape freely into the upper chamber e. These grooves, 
however, taper down to nothing, so that the flow of oil 
through them decreases until none can pass except by leakage 
around the plunger. This allows the plunger with its load 
to settle slowly to the bottom, as shown in Fig. 25 (b ). 

If now the cage is lifted and the weight thus removed from 
the jaw a , the spring g pushes the plunger b outwards and 
allows the oil to run from e back into c. 

Pneumatic Fans.—A pneumatic fan, shown in 
section in Fig. 26, is one in which the shock of the landing 
is partially relieved by a cushion of compressed air. The fan 
is keyed at the bottom to th.e shaft a that rotates it, as in 
















HOISTING, PART 4 


29 


Fig. 24. The cylinder b contains the plunger c , which is 
kept at the top limit of its motion by the spring d. When 
the cage lands in the jaw e , the plunger descends, com¬ 
pressing the air in the cylinder b. The air escapes slowly 
through the iVinch hole /, thus allowing the cage to settle 
into place with very little shock. These fans should be made 
of wrought iron or cast steel so as not to be easily broken. 



28. Cage Chairs. —In the case of a cage required to 
stop at a large number of levels, it is expensive to provide 
fans at each level, and to 
obviate this a strong steel 
bar or dog may be used 
under each corner of the 
cage, all four bars being 
connected to a lever on the 
cage, by means of which 
they can be thrown out at 
will so as to rest on supports 
provided at each level. 

Fig. 27 shows Gray’s patent 
cage chair, which operates 
on this principle. The sli¬ 
ding bars a are connected by 
the cross-bars b , which are 
pivoted at the center and 
operated by the bar c 
through the links d. By 
moving the lever e into the 
position shown, the bars a are thrown out so as to rest in 
notches or on wall plates in the shaft. The springs /, 
through the cross-bars b, force the sliding bars a back under 
the cage when the lever e is released. 


HEAD-FRAMES 

29. A liead-frame of wood, iron, or steel is built over a 
shaft or slope mouth to carry the sheaves over which the 
hoisting ropes are conducted from the mine to the drum of 












30 


HOISTING, PART 4 




Fig. 27 
























































































































HOISTING, PART 4 


31 


the hoisting engine; it also usually carries the upper portion 
of the cage guides or, in the case of a slope, the tracks for 
cars. 

A head-frame must be strong enough to bear the strain 
brought on it due to the total load hoisted and the pull of 
the engine in hoisting this load; it must also be rigid in con¬ 
struction to withstand the severe vibration and shock to which 
it is subjected on account of the rapid hoisting and the jar 
due to the landing of the cages. 

The amount and direction of stresses that a head-frame 
must resist are usually determined by applying the parallelo¬ 
gram of forces as follows: Fig. 28 is a simple head-frame at 



a slope; a is the drum of the hoisting engine with the rope 
coming from its upper side and running over the head- 
sheave b down to the slope cage c. Assuming that the 
angles e , / made by the two portions of the rope with the 
horizontal are equal, and that the pull on each part of the rope 
is 20,000 pounds, to determine the amount and direction 
of the resultant of the two rope pulls, proceed as follows: 
Extend the rope lines to the point of intersection and from 
there lay off the two lines gh andgk, to some definite scale, 
representing the pull of the rope. If a scale of 2,000 pounds 
to iV inch is taken (to inch = 2,000 pounds ),gh and gk will 















32 


HOISTING, PART 4 


each be 1 inch long. Complete the parallelogram by draw¬ 
ing hi parallel to^^ and kl parallel to^*^. The diagonal^"/ 
represents the direction and amount of the force acting on 
the head-frame due to the pull of the two portions of the 
rope. The diagonal, by measurement, is li inches or 
if inches long, and since each tenth inch equals 2,000 pounds, 
the stress on the head-frame in the line of the diagonal^/ is 
2,000 X 15 = 30,000 pounds. The figure also shows that the 

direction of this force is 
vertical, hence there is 
no tendency for the 
frame to be pulled over 
to either side and, theo¬ 
retically, side bracing is 
not needed. 

30. Considernow 
the case of a vertical 
shaft, Fig. 29, in which, 
as before, a is the drum, 
b the head-sheave, c the 
cage, and d the head- 
frame, and assume the 
same pull of 20,000 
pounds on each part of 
the rope. As before, 
extend the lines of the 
rope, which are the lines of force along which the pulls due 
to the engine and the load act, until they intersect at g. 
From this point lay off on these lines distances representing 
the stresses in the rope to any scale. Using the same scale as 
before, tV inch = 2,000 pounds, the lines gli andgk represent¬ 
ing the two forces will be each 1 inch long. Completing the 
parallelogram by drawing hi parallel togk, and k l parallel 
\.o gh, and drawing the diagonal^/ through^, the resultant, 
gl = \o inches, represents a stress of 38,000 pounds. The 
direction of the resultant is also determined, being in the line 
of the diagonal^/. If the head-frame shown in Fig. 28 were 






















HOISTING, PART 4 


33 


used for this case, it would be overturned by this resultant 
force, unless the leg on the opposite side of the shaft from 
the engine were securely anchored, so an inclined brace m is 
added to resist this overturning action. The resultant of all 
forces acting on the head-frame should generally fall within 
the structure if the greatest stability is to be secured, but 
when this cannot be done it is necessary to resist the over¬ 
turning pull by anchoring the head-frame to its foundations 
much more securely than is the case where the resultant falls 
within the structure. 

The direction of the resultant force may be obtained by 




drawing a line through the intersection of the lines of action 
of the forces at^ and the center of the head-sheave b , as may 
be seen in Figs. 28 and 29. 

31. In Figs. 28 and 29, the pull of one hoisting rope 
running from the top of the drum was considered, but in 
most cases it is necessary to consider the pull from two 
hoisting ropes, one running from the top and one from the 
bottom of the drum /, as shown in Fig. 30. a b and a' b' repre¬ 
sent the directions of action of the two forces acting on the 


447-6 














34 


HOISTING, PART 4 


hoisting ropes, while the two vertical forces ac and a' c act¬ 
ing down the shaft are approximately equal to the two forces 
acting toward the drum. There are, therefore, two result¬ 
ants a d and a' d ! , the directons of which are determined by 
lines from a and a' through the center of the sheave e. The 
amounts of these resultant forces can be determined by the 
parallelogram of forces as shown in Figs. 28 and 29. A 
resultant that is a mean between a d and a'd', both in posi¬ 
tion and amount, is sometimes taken, or the greater value as 
determined from ad or a'd' and the greatest inclination as 
given by a' / may be used, as being the worst theoretical 
conditions to which the frame may be subjected. A head- 
frame usually has a vertical post approximately parallel to the 
vertical pull of the rope in the shaft, and an inclined mem¬ 
ber gh approximately parallel to the resultant determined by 
the parallelogram of forces. If gh, Fig. 30, is parallel to the 
resultant, the vertical leg h i is under no strain and merely 
supports the end of gh. If the resultant falls between gh 
and h i, both of these legs will be under compression. If 
the resultant falls outside of gh, the leg gh will be under 
compression and h i will be under tension. The head frame 
will be most stable when the resultant falls between g h and h i, 
but this cannot always be accomplished in building the frame 
on account of the conditions at the head of the shaft; nor is 
it always advisable to do so from structural considerations. 

32. Since wood is much better adapted to withstand 
compressive than tensile stresses and since steel is adapted 
to withstand either tensile or compressive stresses, it is much 
more important that the members of timber frame conform 
as closely as possible to the theoretical line worked out in 
Figs. 28, 29, and 30 than in the case of a steel frame. 
Take, for instance, the case shown in Fig. 31, where for 
some local reason it is impossible to put an inclined strut in 
or near the line of the resultant stress to withstand the pull 
that tends to overturn the head-frame. In a steel structure, 
a can very easily be made a tension member by anchoring 
its lower end to a heavy foundation. This resists the 


HOISTING, PART 4 


35 


tendency to overturn and makes a very stable structure. In 
practice, braces can generally be located parallel to the line 
of resultant strain, Fig. 29, or outside this line, as shown in 
Fig. 30, so that the strain due to the pull of the rope will 
come mainly on the inclined brace and not on the upright. 
To distribute the stress on the foot of the different parts of 



the frame, an inclined brace is usually set farther from the 
shaft than the parallelogram of forces locates it, and so 
placed that about two-thirds of the strain due to the pull of 
the rope comes on the brace and one-third on the upright 
parts of the frame. In order to give the frame a more 
stable base and because the base must be larger than the top 
of the frame to bring the foundations back from the shaft 
mouth, usually the members h i are also slightly inclined. 

Wherever permanency of head-frames is required, if steel 
is obtainable at a price at all comparable with wood, steel 
structures are being used, as timber frames rot. 

















36 


HOISTING, PART 4 


TYPES OF HEAD-FRAMES 

33 . There are three types of head-frame construction— 
the A type , the square type without an inclined brace , and the 
square type with an inclined brace. 

34 . A Type of Head-Frame. —Fig. 32 shows the con¬ 
struction of a triangular, or A-shaped, head-frame of which 
(a) is a side elevation and (£) an end view. This particular 
frame is largely used at anthracite mines, but the type is one 
quite commonly used for timber frames, though the details 
of construction vary in different localities. The height of 
the frame is from 30 to 50 feet, and with direct-acting engines 
this height should be sufficient to allow a play of at least 
two-thirds of a revolution between the cage landing and the 
overwinding point. The posts a are parallel to the hoisting 
rope b as it hangs down the shaft and the inclined brace c, 
which resists any thrust that would tend to rotate the head- 
frame, is parallel to the resultant pull of the two parts of this 
rope b; the inclined braces d stiffen the frame and help sup¬ 
port the cross-timbers m that support the cage guides e. 
The sills / are made of three pieces of timber 8 inches by 
14 inches in cross-section. The posts a rest in cast-iron 
shoes g that are firmly bolted to the posts and sills. The 
inclined braces c , d are fitted with cast-iron shoes h } i. 
The post a and the two braces c , d are held in place at the 
top of the frame by the casting /, which also supports the 
pillow-block k. 

The posts a and the brace c are made up of two pieces of 
timber each 8 inches by 14 inches in cross-section. The 
brace d consists of one piece of timber 8 inches by 14 inches 
in cross-section. The transverse braces / consist of two 
pieces of timber 6 inches by 14 inches in cross-section, 
bolted through the timbers a and c. The supports m for the 
guides are single pieces of 8" X 8" timber. The center post, 
as shown in Fig. 32 (b), is braced by the two pieces n,o , 
which are supported by two timbers p, q bolted to the two 
outside posts. The posts a and the inclined braces c are 



37 


Fro. 32 
















































































































































38 


HOISTING, PART 4 


further braced by the tie-rods r , s, t , and u , all of which are 
fitted with turnbuckles, as shown at v. The different posts 
are firmly bolted together, the bolts being fitted with cast- 
iron washers. 

Fig. 33 shows the construction of the ordinary timber gal¬ 
lows frame used at many ore mines. 

Fig. 34 shows a steel A frame, of which the principal 
dimensions are as follows: height to sheave center 48 feet; 
base 33 feet 10 inches by 56 feet. Legs a and b are made of 



laced channels, as are also the central upright posts and cross¬ 
braces. The forward inclined legs are made of I beams. 
The weight of the frame is 98,000 pounds without the 
sheaves. The advantages claimed for this type of design 
are that it gives a very strongly braced frame while using a 
minimum of material. Also, in cases of overwinding, the 
cage goes over the top of the frame without injury to the 
frame, and should men be overwound they would fall only 
the height of the frame instead of being crushed against 
the top. 

35. Square Type Without Inclined Brace.—Fig. 35 
shows a steel frame in which the tendency to be overturned 
by the pull of the rope is resisted by a nearly vertical tension 
leg as explained in Art. 32. Each leg of the frame is built 











































0 



























































































































































































































































































































































































































HOISTING, PART 4 


39 


of channel bars connected by lattice bracing, as shown, and 
the legs are stiffened by horizontal channel cross-bars sim¬ 
ilarly braced and also by diagonal tie-rods, provided with 
turnbuckles. 

Springs are sometimes placed under the journals of the 



Fig. 34 


head-sheaves to lessen the strain on the rope while starting 
the load; the 15-foot head-sheaves of the Robinson deep 
mine at Johannesburg have locomotive springs under the 
journal boxes, the actual load on each spring due to the 
weight of the sheave, rope, skip, and rock being equal to 
about 20,000 pounds; it was estimated that the sheave would 






40 


HOISTING, PART 4 


thus be lowered by the load on it, about 3 inches, which 
would be equal to an action of a spring - giving motion of 
6 inches at the cage. Springs can often be used both on the 
rope and under the sheave in the same plant to advantage. 



Fig. 36 


36 . Square Type With Inclined Brace.—Fig. 36 
shows a very substantial frame with square tower and inclined 
brace. 








HOISTING, PART 4 


41 


Its principal dimensions are as follows: height to sheave 
center 59 feet 6 inches; base of tower 15 feet 8 inches by 
14 feet; distance of bottom of inclined leg from vertical post 
48 feet. Each end post a is composed of two channels, 



Fig. 37 


double-latticed. The horizontal members b are I beams and 
each inclined member c is made up of two angles. The 
inclined leg d is trussed as shown and built of channel and 
angle beams, the main member being made of two channels, 

447—7 
































42 


HOISTING, PART 4 


the incline and base members of the truss being made up of 
two angles, and the short vertical member of two channels. 
The center post of the tower is similar to the end posts, 
except that the uprights are I beams instead of channels. The 
frame is designed for a static weight of 16,000 pounds and for 
a maximum strain on the cable of 32,000 pounds. 

Fig. 37 shows a .frame of similar form, but in which the 
landing platform is placed at a height above the surface, so 
that the cars hoisted can be run off on a trestle and thus be 
delivered at the top of a car, breaker, tipple, or ore house. 
Its principal dimensions are as follows: height to sheave 
center 75 feet; base 40 feet Ilf inches by 21 feet inches. 
The leg a is made of two angles. The bracing leg b is built 
of two angles. The diagonal braces c are single angles. 
The horizontal braces are angles or channels of various sizes 
depending on the stresses. 

37 . The head-sheave is supported directly on top of 
the main frame, as shown in Figs. 32, 34, 36, and 37, or a 
small superstructure a is built on top of the main frame, as 
shown in Fig. 38, so that the base of the sheave journals is 
perpendicular to the resultant pull on the frame, that is, to 
the theoretical direction of the inclined leg of the frame if 
one is used. 

38 . Timber frames are usually built by the mining com¬ 
pany from its own designs. Steel frames are generally built 
by the structural steel companies from detailed plans and 
designs furnished by the mining company, or from a skeleton 
diagram furnished by the mining company, giving the loads 
on the rope and the general conditions about the shaft to 
to which the frame must conform, the frame being then 
designed and erected in detail by the steel company. 

39 . Enclosing Head-Frames.—Head-frames are some¬ 
times wholly or partially enclosed to protect them and the 
men from the weather. A covering of boards is warmest. 
All woodwork should be painted with fireproof paint and 
ample means for extinguishing fire should be provided. A 
covering of corrugated sheet iron well painted on both sides 


HOISTING, PART 4 


43 


to prevent rusting is often used instead of wood and lessens 
the danger of fire, but is not as warm a covering as wood. 


40. In many states, it is required by law that the top of 
the shaft be protected by a fence or by gates to prevent 



Fig. 38 


persons falling down the shaft. This protection is secured 
at the sides of head-frames by extra timbers or beams form¬ 
ing part of the frame, or by means of a fence placed near the 
sides of the frame. The ends of the shaft are protected by 
a bar placed across uprights, by gates that swing like an 
ordinary door, or more generally by vertical sliding gates 










44 


HOISTING, PART 4 


that are raised by the cage when it comes to the surface and 
drop into place when the cage descends. Similar gates, doors, 
or bars should be used at all landings below the surface. 


HEAD-FRAME SPECIFICATIONS 

41. The following is a sample set of specifications for a 
steel head-frame to be built from detailed plans furnished by 
the mining company. 

This head-frame to be made from drawings to be furnished by the 

-Coal Company, and placed on foundations furnished by said 

company. 

Material.—Structure to be built throughout of soft structural 
steel, net strength 55,000 to 62,000 pounds per square inch; elastic 
limit not less than 30,000 pounds per square inch; elongation, 25 per 
cent.; bending test, bend flat on itself without fracture. 

Builder agrees to guarantee structure to withstand strains specified 
on drawings with factor of safety of 10, to provide for possible over¬ 
winding or sticking in shaft. 

No steel shall be used less than \ inch thick except for lining or 
filling vacant places. 

Workmanship.—The tower to be built in a neat and workman¬ 
like manner. The pitch of the rivets (distance between centers) shall 
not exceed 6 inches or sixteen times the thinnest plate, nor be less than 
three diameters of the rivets. 

The rivets used shall generally be \ inch, f inch, and | inch in 
diameter. 

The distance between edges of any piece and the center of rivet hole 
shall not be less than H inches, except for bars less than 2 \ inches wide; 
when practicable it shall be at least two diameters of the rivet. All 
rivet holes shall be spaced and punched, so that when the several 
parts are assembled together a rivet of ^ inch less diameter than the 
hole can be entered hot into any hole, without reaming or drifting. 
The rivets when driven should fill the holes. The heads must be 
rounded, they must be full and neatly made, and be concentric to the 
rivet hole, and thoroughly pinch the connecting pieces together. Field 
riveting must be reduced to a minimum. All joints and connections 
shall be neatly made, the several parts to be brought together without 
twists, bends, or open joints. 

Inspection.—All facilities for inspecting the material and work¬ 
manship shall be given by the builders during the erection of the head- 
frame. The company reserves the right to reject any or all parts not 
built in accordance with the plans or these specifications. Final 
inspection of work 1 month after being in actual service. 




HOISTING, PART 4 


45 


Painting. —All work, before leaving the shops, shall be thor¬ 
oughly cleaned from all loose rust and scale, and be given one good 
coat of paint well worked into all joints and open spaces. In riveted 
ironwork, the surfaces coming in contact shall each be painted before 
being riveted together. Bottoms of bearing plates and any parts that 
are not accessible for painting after erection shall have two coats of 
paint. After the structure is erected in place, it shall be given one coat 
of paint. All recesses that will retain water, or through which water 
can enter, must be filled with thick paint or some waterproof cement 
before receiving the final painting. The paint shall be a lampblack 
paint, mixed with pure linseed oil, or of red lead mixed with raw lin¬ 
seed oil containing Japan dryer. 

General Clauses. —The specifications and drawings are intended 
to cooperate and to indicate the principal dimensions and requirements 
necessary to the complete structure. It being understood that while 
some work may be shown in the plans and not described in the speci¬ 
fications, or vice versa, and some minor details and fastenings are 
omitted from both plans and specifications, the work is to be executed 
without extra charge therefor, the same as if the minutest details were 
set forth in full in both drawings and specifications. The contractor 
is to make good any defects of material or workmanship developing 
within 1 year after final acceptance. 

The contractor shall furnish a location plan and also two copies 
of the detail shop drawings for convenience in making future altera¬ 
tions and repairs. 

Erection. —The head-frame is to be erected complete, secured to 
foundations provided by the_Company. 

Contractor shall furnish all foundation bolts and washers. Iron 
stairway with hand rails beside main back bracers and platform with 
wooden floor under sheaves, also iron stairs from platform under 
sheaves to back sheave pedestal for oiling. Wood furnished by the 
__ Company. 

Price includes all material for completion of work delivered, erected, 
and riveted in place and painted. 

The_Company will furnish and place in position the sheaves, 

with the shafts and boxes belonging to the same, also the wooden 
guides. 

Delivery. —The head-frame to be erected, complete, and secured 
to foundations in . weeks from date of order. 



46 


HOISTING, PART 4 


DETACHING IIOOKS 

42. In hoisting, there is more or less danger of over¬ 
winding or lifting the cage too far, and dashing it against 
the top of the head-frame, or if the top is open the cage may 
be pulled entirely over the top. Detaching hooks are 
intended to prevent this. Several varieties of such hooks 




are made, which differ from each other only in their smaller 
details. In all of them, detachment is effected by passing 
the rope through a circular hole in an iron plate or through 
an iron cylinder, the diameter of which is sufficient to allow 
the upper portion of the hooks to pass through when passing 
upwards, but the lower portion is made larger and so 
arranged that when this larger part strikes the plate the 
upper portion is forced open and the hoisting rope released. 
After the upper part has been thus opened, it is too large to 




































HOISTING, PART 4 


47 


pass back through the opening and the plate and the cage is 
therefore held suspended. Fig. 39 shows such a hook. It 
consists of two outside fixed plates slightly narrower at the 
top than the diameter of the hole in the disengaging plate h. 
Between the frame plates a are two inner plates b that move 
about a strong pin c passing through both plates a and b , but 
near the bottoms there are two projections d to prevent the 
hook from passing entirely through the hole. The winding 
rope is attached to the top shackle e and the cage to the 
lower shackle /. When the two movable plates b are closed' 
as tightly as possible at the top about the pin of the shackle e , 
they are secured by a copper pin g. In case of overwinding, 
when the hook passes into the hole of the disengaging 
plate h, the two projections k on plates b are pressed inwards, 
shearing off the copper pin g and allowing the plates b to 
turn about the central bolt c, thus releasing the shackle e. 
The plates b are then in such a position that the projections / 
on them cannot pass down through the hole. The cage then 
hangs by the hooks from the disengaging plate, and the 
rope passes on. An objection raised against this hook is 
that, being constructed of plates, there is considerable sur¬ 
face in contact between the moving parts, and unless they 
are regularly taken apart and oiled, there is danger of their 
rusting firmly together. 

In England, detaching hooks are used quite commonly, 
and also in certain parts of the Central Basin in the United 
States, but they have not yet been generally adopted 
throughout the United States. 

43. It is claimed by many that such devices inspire the 
engineer with a misleading feeling of security; that they are 
more or less complicated in construction and so need care, 
and destroy the simplicity of the plant; that they may be the 
direct cause of accident by introducing new elements of 
danger; that they add to the cost; and that they are not 
thoroughly reliable. Again, it is held that the surest preven¬ 
tion of overwinding is obtained by the employment of a sober, 
reliable, and competent engineer, who is held personally 


48 


HOISTING, PART 4 


responsible for overwinding accidents; by having a good 
brake and an engine thoroughly under the control of the 
engineer; by a reliable method of indicating the position of 
the cage; by sufficient height to head-sheaves to allow of 
considerable hoisting over and above that necessary for 
landing. 


SIGNALING 

44. Some method must be provided for communicating 
between the bottom or any level of a shaft and the top land¬ 
ing or the engine room, also between the top landing and the 
engine room, so that the hoisting engineer may be notified 



when both the head-man and foot-man are ready for him to 
hoist. A common method of signaling is by means of a gong, 
bell, or triangle placed in the engine room and connected by 
a wire or small wire rope with the point from which it is 
desired to signal. Attempts have been made in different 
localities and by different associations to adopt a standard 
code of hoisting signals, and while it would be advantageous 
if this could be done, none of the attempts made have been 
entirely successful. Although there is no uniform system of 
signals, one bell generally means stop, two bells lower, three 
bells hoist, and four bells hoist men. 

45. Hammer-and-Plate Signal.—Fig. 40 shows a 
hammer-and-plate signal, the plate being a piece of boiler 
iron or steel. The hammer is often located beneath the plate 




HOISTING, PART 4 


49 


instead of above, as shown. Another style of hammer and 
plate is shown in Fig. 41. The hammer is made of 2-inch 
square iron and heavy enough to balance the weight of wire 
hanging in the shaft and to take the sag out of the horizontal 
wire connecting the top of the shaft with the lever a . A 
simple dial turned by a ratchet motion 
attached to the lever a is sometimes 
used to show the number of strokes, 
and thus check the number counted by 




Fig. 41 


Fig.42 


the engineer. The dial is reset by the engineer as soon as 
he understands the signal. 


46. Electric Bells. —Electric bells operated by push 
buttons are rapidly coming into use for mine signaling on 
account of the ease and completeness with which such 
a system can be installed. Electric flash lights are also 
extensively used for signaling purposes. The principle of 






























































50 


HOISTING, PART 4 


action and details of the wiring for electric signals and flash 
lights have been described in Transmission , Signalnig, and 
Lighting. 

47. Speaking Tubes. —The laws of certain states 
require speaking tubes, in addition to the ordinary means of 
signaling. These speaking tubes are generally made of 
2-inch iron pipe and are from 300 to 1,500 feet long, and are 

often provided with 
whistles at the end of 
the pipe and at each 
level of the mine, by 
which the attention of 
persons at any level can 
be attracted or the 
whistle may be omitted 
and the attention of per¬ 
sons attracted merely 
by rapping on the pipe 
with a piece of iron. 

48 . Pneumatic 

Gong Signal.— Fig. 42 
shows an attachment 
that can be connected 
to a speaking tube and 
that is widely used for 
signaling. It consists 
of a brass cylinder a 
fitted with a piston b 
containing valves c. 
The gong d is attached 
to the cylinder e inside of which the clapper / fits loosely. 
When the piston is pushed inwards, as shown by the arrow, 
by means of the handle, the air in the cylinder and in the pipe 
h is compressed and forces the clapper / upwards against the 
gong d. The arrangement of these gongs in the mine is 
shown in Fig. 43. A cylinder and whistle are usually placed 
at each .landing and a gong and whistle in the engine room, 





fiHi 




Fig. 43 
































HOISTING, PART 4 


51 


though, if desired, a cylinder, whistle, and gong may be 
placed at each landing and in the engine room. 

49. Telephones. —Telephones connecting the different 
levels with the top and the engine room are now frequently 
used in connection with other signal systems, but they are 
not as well adapted as bells or gongs for rapid-hoisting 
signaling. 


























































